Older man?

Hey everyone, just a quick question! So I am currently in a relationship with an older man, something I would have NEVER thought of doing before! He just turned 27, and I am 19. He has a 3 year old son, he fought for full custody of. (Great dad) he has a great job, etc. Just a good guy all around! Weird part is, I've known him my entire life! He is my older brothers best friend. But just 2 months ago, he face booked me and asked for a date. So I would really just like some thoughts on this! My family is alright with it, but I do have some friends saying I'm crazy. Am I crazy?? lol. Feedback greatly appreciated:)