I’m conflicted… should I risk it?

So… there’s this person whom I’ve known for a long time. We were close friends since elementary school and always got along and stuff. They’re sweet, and caring, and we make each other laugh. Things sort of changed in high school, when they told me that they had a crush on me. At the time, I wasn’t ready to be in a relationship, (you know, being young and dumb) and I turned them down as gently I could. We stopped communicating for a while after it… until recently. We started talking again and reconciled after what had happened, and reforged our friendship. We realized how much we had missed one another, and things seemed back to normal and great! But now… I’m beginning to realize that I like them. At first I tried to ignore it, but after we reconnected and started hanging out again, the feelings just kept growing. They told me that they don’t have a crush on me anymore… but they send me strange mixed signals, wether it be the way they look at me or little comments, or actions. I guess a small part of me wants to believe that they’re still interested, and only said they weren’t because they were afraid I would turn them down again. I’m scared. I want to tell them that I like them… maybe even love them. But what if they really meant they weren’t interested anymore? I don’t want to ruin our friendship when we only just reforged it! I can’t help but think back to when I first turned them down, and I’m kicking myself—if I had known how I would feel a couple years down the line, I never would have… I feel like I screwed up permanently, like there’s no way I can fix it now. I don’t know what to do. Should I tell them, or should I just keep quiet? I’m so conflicted.