Classic guitar with steel strings?

I'm almost 13 and I want to start playing guitar. I was looking to get a steel string flat top acoustic, but I can't get one for now due to money issues. So I'm stuck with a classic guitar. My first question is, why does my classic guitar have steel strings? And my second question is can I play modern music on my classic guitar? Like indie rock,, R&B, ect ect? Some songs I would like to play are Who You Are by Jessie J, Rolling In The Deep by Adele and Im Yours by Jason Mraz, so you get the idea of what I mean by "modern". Can those be played on a classic guitar?