What a jerk.
I'd slap him upside the head if I could!!!!! Glad to hear your mum is supportive though, so that you're not on your own! Hopefully he comes around hun!
Generally, from what I've read from other girls, you'll have your first scan around 12 weeks. It's a little different here in Canada, you get the 12 week scan if you're unsure of when you concieved..
Usually one around 12 weeks, and again around 20. Shouldn't be any different if you're 15 or 30, unless ofcourse they determine you're high risk! But otherwise, you'd be going about everything and your appointments just like everyone else would!