One of my parents old bikes. What would you say?

Hello. I'm 15, kinda new to bikes. Here's one of my parents old bike. It was bought in 2006, don't know for how much, and I think it was put to storage and never seen trails since 2010. It's still in a very good condition, regarding of how much it stayed in old cold garage. I only changed the seat and seatpost (old was stolen last year!) and put a little speedometer thingy. So… what can you say about it? How much is it worth? I'm not planning on selling it, just want to know what I'm riding