Today I told my boyfriend that I'm pregnant

It's his birthday today and I decided to tell him the news after he blew out the candles on the cake. He was so excited, he hugged me and told me that he's ready to be a dad. Whenever I thought about being a parent I always pictured it with him. So, I thought I was doing the right thing. I thought I was making the right choice to tell him. I was wrong. I'm only 18 and I didn't expect to get pregnant so soon. I didn't even consider whether he wanted kids at this point in his life. I knew he didn't but I didn't really care, I just assumed he would be okay with it, and I didn't want to ruin his birthday. He's always wanted kids so I thought he would be fine with it. I didn't even think about how he would feel. He's 20 and has a kid on the way. I ruined his birthday with the news that he has to take on so so much responsibility. I can see the stress in his eyes but he's so good at hiding it. He doesn't want the kid, I know. He doesn't want this responsibility. I made him cry for godsake.