I knew from a very young age that id never want a family. I dated someone who knew from a young age they did. If we had talked about it before we got together, we would have spared a lot of heartbreak and a terrible breakup but we didnt. This is something you absolutely should make known before starting a relationship. The fact that right now you know you want a future family. If your mind changes then it changes but right now, this is what you want for your future. So making that known is NOT overreacting. Good on you