Start shooting speed every day.

Give up and instead try to get a role as spider man

Have kids. Hair started falling out by the time she was 2

start smoking and drinking, cut back on sleep and find an unfulfilling stressful and thankless job that also underpays. throw in some women/partner/spouse that treat you like shit to really speed this up.

Youth is wasted on the young.

smoke cigarettes. like...a lot.

meth while you're at it.

or, count your blessings.

I knew a kid who had straight up male pattern balding at 16. by 18 he had a horseshoe. dude looked like he was in his fifties before he was out of his teens.

I think there is a few things you can do. I do think the best and healthiest thing is to just take it as a compliment, but keep your ID close if your are doing something that needs verifying.

But, if you(or someone), doesnt like it, and it is causing you issues mentally(perfectly valid). Then you can not shave as close or as often, works better the thinker and more consistent your stubble is.

Dress older, this is a lot more expensive, but can look at things like chinos and relaxed jeans with polo shirts or as we are approaching winter more knitwear, you would also be looking at boat shoes or loafers. You may also find that Hats make you look older as well.

The final one is a bit more tricky, your hairstyle. Change that to be a bit longer and "scruffy"(think around the ears a bit more) or if you have a good head shape, go short or bald. This could also have the complete opposite effect as well, and further highlight the baby face though.

Bonus bad idea, get so much sun on your face it starts to go all leathery. May have a slight side effect of cancer though.

Have kids. The people with kids who are ten years younger than me look twenty years older than me.

Life isn't a race. Hold onto your youth and don't peak early, stay whimsical and have fun

Once you're actually old, you'll be glad that it's at least a new experience

It's all about what you wear.

White New Balance 608s, jorts, and a graphic tee about sarcasm or puns. Make sure your 608s are stained a little green from mowing the lawn.

Route every conversation back to your lawn, lawnmowers, or the Traeger/Blackstone you want to buy when your wife let's you.

Literally that easy.

Just enjoy it while it lasts. People have consistently estimated me 10 years younger than my real age for decades. Well, until now, since I'm getting some grey hairs.

Hang on to that shit as long as you can.

Caring about how old people are or look is a young person's game.

When you go "What? Of course I know today is Tuesday.. Oh yeah you're right, it is my birthday. Nah, just an early night for me.", no one will think you're a high schooler.

But style choices, posture, glasses and other accessories can make a difference as well.

Or just take thinning shears to your temples and crown, and go for a balding look.

Just wait…

A good haircut can help. Get one that fits your face better than whatever standard cut you've had since middleschool or earlier.

Fat hides change. Get fit.

A lot of the difference between hs and mid 20s is largely about demeanor. How you carry yourself with a bit more knowledge about who you are.

Wear new balance shoes, or sandals with socks.

Hi!!

Not sure of your complexion, but a tan could make you look a bit older.

A hair cut that fits your face shape is another thing that could age you up as well.

Other than that, I say the clothes you wear, but that can be hit or miss.

Spend long hours under the scorching sun with no protection. The irreversible damage caused by UV light will make your skin look significantly older. Bonus points for not using sunglasses, so your vision can deteriorate faster too.

I don't think I need to say this, but just in case: do not actually do that.

Also, I too used to think "I can't grow a beard" due to thin and not very dense facial hair, but if you say "screw it" and do it anyway, it eventually works out (unless your reason is different). It'll look like absolute shit for a while, but once the slower growing areas catch up, it's not that bad.

You can do it with a toothbrush. Just brush your teeth twice a day and you'll look older sooner than you expect. It's actually pretty annoying. You get all kinds of infirmities to help you act the part. Enjoy your youthful good looks while they last.

We wait ten to twelve years.

Stress.

A lot is how you dress and act. Act with authority, wear professional type clothes.

I also thought my facial hair was shit until I let it grow and it was pretty okay, and people told me I look 30 whereas before I looked around 20. Never went back to clean shaven ever. My moustache and beard are patchy as fuck but still better than looking like a fucking toddler

Tuck your t-shirt into your jeans

One of these?

Wait and let time take care of that.

Needing to look older isn't something you need to do unless you're an actor or a 16 year old trying to buy beer.

Start smoking Marlboro Red 100's. Them cowboy killers are guaranteed to add at least a decade to that face of yours.

Just start greying in your teens like I did.
Really people mostly respond to how you carry yourself. Walk around like you know more about where you are at than anyone else and people will believe it.

Lifting weights? Dressing more business casual, perhaps. That’s a tough one.

Look "professional" tends to help. It's an overton window some, you'll want to find the most professional you can look for what your face and body type. But you are essentially try to look like you are in a later stage in your career which people, because it takes time, associate with older people.

Adding some muscle mass can help (you know towards dad bod no need for body builder shenanigans).

Some old guy tricks are wearing smart pragmatic clothing, but are kind of commiting to the bit of being comfortable being an adult. So suspenders/belts to keep your pants up, fanny packs to store stuff you need on the go (medical kit, snacks), somewhere to have a pen, a utility knife, etc. Glasses if you need them. Hats that keep the weather off of you appropriate to your region. Etc

We've been placing our finger over our top lip as a mustache for generations, I'd start by doing that regularly. Will add 5 years ezpz

Clothing is a good bet. Someone who's more up to date on fashion trends may have better advice but button-ups are usually like $5-10 at thrift shops. Any color of plaid with the sleeves rolled up and the top 2 buttons undone is casual enough for most situations.

And if you can grow a beard but it's slightly patchy, see a barber or cosmetologist that does brow and hair fill-ins with henna. It'll be a little pricey the first time but ask and pay attention to how they apply it based on your needs then just buy the henna yourself. It's temporary, won't hurt your skin, and will get you through the next few years until you can grow a fuller one. It also helps to have it uniformly trimmed and 'edged up.' You'd think cutting it would make it look patchier but the trimming will prevent long wispy hairs accentuating the shortness of the patches and having it edged up will give better contrast against your skin.