If your Dad has been in prison for a long time he may feel that he doesn't really know you now that you have become a young adult..
It will take time for you and your Dad to get to know each other again.
Is it possible for you to talk to your Dad about this? If you let him see that you understand how he must be feeling, he might find it easier to be open with you about his feelings and hopefully you could both work on getting close again.
Maybe you could say to him something along the lines of "I suppose I must seem very different to you now, compared to the child I was last time you were living at home". That might open up the conversation.
Is there anyone you can talk to about this? Maybe a social worker or prisoners' liaison worker? I think it would probably help both you and your Dad if you were able to talk about your feelings. It is a big adjustment for both of you.