You’re right, he isn’t mature enough yet to handle different situations properly. You’ll need a lot of patience and understanding until he learns how to deal with the various challenges you’ll face in life together.
For now, just continue guiding him on how to become a more mature person, but do it in a way that won’t offend him. Help him realize the things you’ve learned from your own experiences before you became this strong and resilient.
In that way, he will better understand where you’re coming from without feeling hurt or threatened. This can also help strengthen your relationship even more.