Dualbooting is great. Whole idea of linux is "you can tinker in any way you see fit" and putting multiple OS on a single computer is one example.

Fact that you did this at 15 is impressive btw. Willing to mess around with computers is a real skill. Half the CS students in my college had hard time setting up a fedora VM by themselves for UNIX class.

You are already ahead of actual college students in this field lol. You learnt more about computers thanks to old GPU.