I started on a 50mm pole, and tried to use it as much as possible ever since. There was a period of time when I did spinny classes on a 45mm pole, which was SOOOO much easier, but the moment I tried to switch back to 50mm it was horrendous. I find that I needed so much more strength to be able to do moves that I can easily do on a 45mm.
Now I do pretty much everything on 50mm, including spinny routines. However, when I have difficulty with certain moves (like now I’m trying to get my twisted grip handspring), I go back to the 45mm, and only when I can do it there then do I try to get it on the 50. To me, I’ve only nailed a move if I can do it on a 50.
So, for me I’ll advise you to continue on a 50. It’s harder certainly, but it’ll make you so much stronger. Which is always a good thing 😊😊