At this time 61 keys is certainly more than enough to learn to play well. If after awhile you progress to where you are playing more advanced music and you start running out of keys then you can always get 76 or 88 keys. That would probably take a quite awhile and a lot of advanced hobbyists and pros alike are very comfortable playing 61 keys. As a general rule of thumb in the music business it is pretty much an accepted idea that no one needs 88 keys unless they are playing heavy classical music or something along those lines.