Telling my mom


So I've been seeing this guy recently and I think we're really hitting it off. The thing that I know my family will be disapproving of is that he has a 10 month old son. I am 17 and he is 19. I am nervous to tell my mom because she is a very opinionated person. I know I want and need to be upfront with her for this new relationship to work but if anyone has any advice on how to bring it up to her that would be very appreciated!