The trouble with this is that pop songs are not in the public domain so you would be infringing copyright by posting public recordings of yourself performing them, even if you have created your own arrangements of them.. To do this legally you would need to apply for permission and pay a licence fee to the copyright holders.
An alternative you may want to consider is YouTube. If you wanted to target children specifically, you could record free piano lessons for how to play hit pop songs, etc. Then offer your private tutoring at the end of each video. You can get some decent organic traffic from piggybacking on searches for pop songs. You can also boost your results with paid YouTube ads
Also You can do quality good instagram videos, use hashtags "Pianoguys,landsey striling, Piano, Piano teaching" etc
ETA: to publicly perform, record, arrange or copy any musical works that are still protected by copyright, you need to apply for permission from the copyright holder in order to comply with the law.