Young and embarrassed

I'm 22, graduated from college and a few weeks ago my boyfriend and I found out we were pregnant. After a lot of discussion and arguing I've made the decision to keep the baby with his support. Almost a weeks ago we told both sets of our parents about the pregnancy. We were overwhelmed with support from both sets of parents but for some reason, even though I'm 22, I found myself feeling embarrassed that I'm pregnant and we didn't plan this. My older sister got engaged today and my parents were over the moon happy for her as am I, but it makes me feel as though they're starting their lives the way they're supposed to and I'm going to be playing house with my boyfriend and our new baby. I feel like I'm just so young and people won't take me seriously as a mother. Did anyone else experience embarrassment about their unexpected pregnancy? What made you feel more confident?