I wouldn't say "jerk", but maybe a little insensitive to supporting his dreams. The hard part about being a parent is that your kid needs to fail sometimes, and your protesting to the failing will only create a divide between you two. Offering advice once is totally fine, but continuing will make the situation worse. He will likely fail pursuing his dream, and reality will hit him hard afterwards, but that's ok. Just make sure he has your support, and he knows you love him.
It doesn't matter that you've learned this life lesson already. He hasn't. Sometimes, you have to learn the hard way for it to stick.
Fist bumps, obviously.