Annapurna is a spectacular area to trek. I've done it twice, but not as high an elevation as they went.
My first time I had hired a private guide in Pokhara. Made a mistake listening to him, since he was determined to get me to a specific tea house for the night. Rather than stop early my first day when I got sore, like I should have, he pushed me to keep going up.
I learned later that some of the guides have certain businesses on the mountain where they get kickbacks in the form of free food, etc, and will pressure you to stay at that specific one. I should have listened to my body, and stopped at a lower tea house for the night. Since I kept going, I was so sore the next day, that the rest of my trek was a miserable experience.
Also, coming back down the mountain was actually more painful because it takes as much or more muscle power to stop yourself from falling than it does to climb up the mountain. If you go, listen to your own body. The guides might have other interests than your health,