Just found out GF is really 17. What should I do?

My girlfriend and I have been together for 7 months and I do love her. I'm 22. I will be 23 next month. When we first met, she told me she was 18 going on 19 and a freshman in college. Well, we found out that she is pregnant and I guess she decided to tell me the truth. She is really 17. When I met her, she was only 16. (she does look and at like a 20 yr old.) Also, she's not a college freshman but a high school junior. I don't know what to do. It's like I'm mad, sad, shocked, depressed, etc. all at once. I feel like i've been wronged, but I'm doing something wrong as well. I don't know what to think. We did argue and she said that I was stressing over nothing. But this is considered as rape, yes? Plus, there is a kid in the equation, which I honestly don't mind. I'm already taking the proper steps so I can be a great father. I fell stupid. It's like our relationship has been based on a lie. She loves me and I love her, but I just don't know what to do. Any advice or insight whether condoning or condemning me would be helpful. Thanks in advance. BTW: I'm not some dead-beat guy. I only have 1/2 year left until I obtain my BS. YYAAAY!

Milynir Tweet