Wow this is a heavy discussion
Coming from a Christian family who wanted the same for me I kind of understand where your coming from, me and my girlfriend were planning on waiting but I guess hormones got in the way, we ended up having sex roughly 2 years into our relationship I told my dad (he was fairly ok about it) Mum was upset but I guess there was nothing they could do about it. Where you parents Christian from a young age that kind of affects there attitude my parents became at a later point in life so they understand the sexual liberation that our modern society!!
I think its cool your getting married, I got some friends getting married in a couple of months both under 20, they don’t have much of a career at the moment but sometimes I guess all you need is love and a little help from your friends & family.
Good luck!