but he says that it will work out.

What does "working out" mean? Realistically, his music career will never take off. He might have a bit of side-income, but will it be enough to pay into a pension fund, start saving for a baby, a house etc.? What sort of lifestyle does he imagine having later on?

. Thats why im going back to school to have a career that will help me start saving up and to provide.

What sort of family dynamic do you imagine in the future? Would you like to stay home with your child for a bit? Would you encourage your partner to stay home for a bit? How do you feel about your partner not working towards increasing his income in a more stable way? How will you feel if it's mainly you saving up for a future?

And he does not want to talk about wedding stuff. We want to have just close friends and family but he said he wants to spend more than 15k to give me the wedding I want, which I hope doesnt cost that much

While you're still young, you've been dating for a while, and given a big wedding is important to him, he should be able to have discussions about it even now.

"just" close friends and family can mean anything.... also, why more than 15k? Where did he get that number from? Why not do some actual research about costs of venues, legal fees, renting/buying a suit/dress second-hand/new, catering fees, decoration etc.?