After wearing about 19 out 31 of my Invisalign trays I needed a new set of aligners. This one contains 52 trays.

I started my Invisalign treatment last year, with a total of 31 trays. Around the 19th tray, the aligners stopped fitting so I needed to get new impressions and a new set of trays. The new set now contains 52 total trays. That will put my total time wearing Invisalign at at least 72 weeks. Is that normal? My teeth were a little crowded and I had a bit of an overbite, but nothing too extreme. I am 26 years old. Thank you!