Got hit on while at work

So today at work I got hit on by some random guy. This is pretty much the first time I've ever gotten hit on btw. I'm a senior in high school and he looked like he was around 23 but he could've been younger. Anyways he just came up to me and started flirting with me and then asked for my number. I told him no because I don't give my phone number to any random person, but then he walked off all butt hurt and now I just feel bad. But then again I feel that it's a little creepy to hit on someone while they're at work. I'm even scared to go back to work (I work in a toy shop in the mall btw) in case he's gonna be there. I really don't want him to talk to me again because that's just awkward. What are your guys' experience with being hit on? What did you do? I just feel weird about it, especially since he was obviously older than me. I mean I did look super bored so maybe that's why he went up to me or maybe his friend dared him. Idk