Hey, been there, done that.
INTP's do not mature overnight (does anyone?

), their maturing process is long. It's a very complicated Ti process that takes a lot of time. Part of growing up is questioning every aspect of your life that feels out of place. You bringing up this topic for example. But it's far more then that. It's several years of topics like these roaming around in your mind.
This is very healthy for an INTP.
Don't expect to grow up in a year or two or whatever, just keep being yourself, keep questioning everything you feel the need to question, and develop yourself accordingly. You will reach a stage where you are much more comfortable with who you are.
Also, try to see new experiences as learning oppertunities. So you don't shy away from new things too easily. It's okay to make your Ti push you ahead of your Ne from time to time. But do know that this can be very tiring at times, take time outs if you need them to process and analyze.
