It depends on "how" he is following you. Is following you like he's excited he may be getting a treat and bumbling along behind you? Or is he following you in a stealthy way like he's trying to read your moves and his attention is focused totally on you?
You're questioning why he's following you. Does the following make you feel uneasy? If so, he's possibly measuring you up and you're instincts are reading his movements correctly. A rooster who's sizing you up will make you feel like the equivalent of someone's who's following you with the intent to rob you.
It's a funny comparison...but it's exactly the way I feel with one rooster I have right now. He's sneaky and is always watching for an opportunity to spike me. He is a cull rooster. I just haven't dealt with him yet...lol.
You mentioned you just got him. Do you know the background of how he was handled? Perhaps the previous owners gave him treats...or similar attention and he is just acting as he has with them.
I have many roosters who haven't got an aggressive bone in their body towards humans and they happily trot along with me. I have a couple who come running right up to me to get hugged. Their demeanor is very happy go lucky. I know this. But a person who wasn't familiar with them could take their actions as aggression...especially the ones that come running up.
In the mean time...wear tall rubber boots if you have concerns. That will at least protect your lower legs should he show aggression.