Is it wrong/bad that I am spending time with a girl who reminds me immensely of a girl I used to be kind of in love with?

I’m not entirely sure if it’s the REASON I’m spending time with her, but a part of me feels like I wouldn’t be if she didn’t remind me of the other girl. The two are so similiar it freaks me out and I’m wondering, is this a bad idea for ME to do this, and is it unfair to the girl I’m seeing now?