Scared of the future.. I need reassuring words

Im 17, 18 in 4 months. I received an email from a university that I can enroll into. I’m afraid of growing up. I’m afraid of losing my best friend because we’ll go separate ways. He’s joining the Navy & I don’t even have my thoughts together. Idk what I want to do.. I wanted to be an anthropologist but a teacher basically discouraged me asking me how am I supposed to make a living. He may have a point. I don’t want to waste my years trying to study for a career and not get it. I’m afraid of what the future holds for me. It can go wrong and I don’t want it to..