Form is also important. Read all official guidance carefully, so you incoporate proper form from the start and avoid bad habits. Bad form>rep doesn’t count.
Google “Stew Smith CFA.” Stew is a former Navy SEAL, USNA grad and now a fitness professional.
USMA has a good video out on the CFA; browse through YouTube looking for others with tips on building up. Found the USMA one, note the form comments:
Work on your grip strength too, separately. That is a key contributor. If your hands have the strength to hang on, you can focus on other elements. If your hands are screaming “ouch,” that can be discouraging.
I am logging my 6th decade on the planet. I happen to be a woman. I learned to do these before I went to OCS, and similar to push-ups, planks, crunches, etc., never stopped doing them. My dad put up a pull-up bar in the side door to the garage, and I’d go out there every night after dinner to jump rope to harden my legs and build stamina, and try pull-ups. I’ve let my max tail off over the last decade, but still work them in 2-3 times a week at the gym. I like using the assisted pull-up machine (with no assist), though one day I will no doubt need the assist again. I bless the Navy for instilling a lifelong fitness habit in me.
You CAN do these. You WILL feel great when you get that first one, then the next ones. This strength enabled me to handle all kinds of physical challenges later on, and I still easily lift big dog food bags, water system salt bags, etc.
Check back in to celebrate progress.