Is my mom right to be mad at me?

My friend and I went to the park at 8:30. We didn't take our phones because she didn't have any pockets and my phone didn't fit very well in mine. So we went to the park, had a good time. It wasn't dark when we left. So we got back to my house a little before 10:30 JUST as my mom was driving away. We waved but she didn't see us. So I went to my neighbor's and called her (since we didn't have our phones). My mom is now EXTREMELY mad and says I'm not allowed to go to the park anymore because we were supposed to be home before dark. The thing is, she never told us that because she assumed we already knew. I'd briefly considered the possibility of it bothering her, but I didn't think it would because she's been reliving her youth lately and it just seemed... acceptable. I understand that she was worried but I think it's highly unreasonable that I'm no longer allowed to go to the park. My friend and I are almost 15 by the way. Who's right, who's wrong, and how can I fix this?