Is it normal for Chicks to watch ? My girlfriend watches . I thought it was for guys only. why girls?

I was just wondering, i was watching at my friends house, Maddie 14,(I'm 15) my girlfriend walked into the bedroom and saw me wtching a video, and me with a pump. unlike most girls, she wasnt surprised She seemed interested and wanted to watch them with me. Is this normal, she's freaking me out..