creepy guy?

so i live in a fairly small apartment complex, and the buildings are small (4 apartments each) and close together. last night, i was walking inside with my dog at about 10pm. a guy in the building next to me was walking inside too, and i had headphones in. i saw him saying something, so i took an earbud our and he’s saying “how old are you??” i didn’t know why he was asking and it was kind of creepy, so I walked inside. today at about 4, i was walking my dog, and he was sitting on the curb outside his apartment smoking. i got a better look at him, he looks like he’s maybe in his 30s, skinny, face tattoos. i had an earbud out, and he said “hi. how old are you?” i said “14.....” he said “have a nice day. i walked away, and it was really creepy. why is he asking me? what should i do? i didn’t tell my dad because he was at a friend’s last night and at work today. does anyone know why he was asking me?