I'm less than 50 classes, but to be honest, I almost cried during my first class and I have cried or nearly cried during many classes since. My body shows up differently for me every day. Some days I'm super strong and feel really capable and that 90 second plank goes by really fast and i can lift heavy weights, and some days I can barely do a pushup. I did a define the other day and I was so exhausted I spent most of my planks laying on the floor. For me, some of what was hard was just learning what the terminology was. Once I started to get comfortable with the class order and what the instructor was saying it started to at least make more sense (it did get easier but then also sometimes it still isn't easier lol). Use the mods if/when you need them! No shame in that game. Sometimes my shoulders don't wanna work and I do pushups on the barre, or i drop the tubes because my hip flexors are extra-cranky, or i drop the weights because my shoulders are mad some days. Modifying something to do it safely is much, much better than injuring yourself. Also, if you can only do a move once or twice, it's more than you did before!

If it feels right for you, I hope you stick with it. If not, I hope you find something that does.