18 and pregnant

I am 18 and just recently found out I am 4 weeks and 6 days pregnant. My boyfriend and I have been together for over a year and we are both very "well off" financially as I have been blessed with wounderful promotions at my job, same with my boyfriend. I graduated high school early and started college right after! (Not kidding, I graduated HS on a Friday and started college Monday). I feel as if for my age I am on a good path. I am just struggling with how my boyfriend and I are going to tell our parents. My mother was 15 when she got pregnant with my older sister and then had me at 18 so I feel as if she will be more understanding in that aspect. However my boyfriends parents are the exact opposite. Waiting until marriage to have children and just did ever everything the "right way". My boyfriend and I are nervous but we both agree that this is a blessing. Does anyone have any advice on how to break the news? Also when should we tell them?