Real Mature Kids.

You're fifteen. She's sixteen (just). You do NOT get to plan to get married or have kids. Get a life and be mature!
You want to crack the shits with me? Go ahead: Prove my point.
You may not ask a lot but you ask it often and it adds up to one big heap of "I can't be fucked any more". I honestly don't give a shit if he calls you or if you call him. It's not my business nor is it my job to care. So keep me out of it.
I never boss you around over your relationship. I only ever tell you what displeases me about it. I don't have to be happy with your stupid "I wuvv yous" or pet names. Again, it's none of my business.
I don't hate you for being with my brother. I hate that you are both being ridiculously immature about your relationship. You were told NOT to have sex for a reason. The reason is that you could end up with consequences that need to be carried around for nearly ten months. You are not mature enough for that. Neither of you are.
You want to get married. You're even engaged. You're also very, very stupid and naive. Go ahead and be in love but don't expect much support. You two need to grow up a great deal before you are in any way ready to be partnered FOR LIFE.
Do you know what that scare cost this family?
If you can't even follow correct English conventions, how the hell are you supposed to prove you can make MATURE decisions in your life? You want to be a big girl and man up to what you did? Do your parents know what happened? Or don't they need to, right?
Your family IS my family if you want to be mature about your relationship. I'm not putting this on you. I'm putting it on you AND Scott. It takes two to have sex.
Try screwing up your life on your own time when we no longer count.