@youngchristianfemale If you're currently only able to do three pull ups a set, then, IMO, you shouldn't be doing fully unsupported pull ups yet..
Try getting a chair / something to stand on and use your legs to help you up, with the goal of doing 6-8 reps, and a total of 2-3 sets in one go (40-45 second rest between sets). You'll want to provide JUST enough leg support so that you're still working hard for those 6-8 reps (otherwise you'll be taking away from max potential gains). As time goes by, use less and less leg support until eventually you're able to do a full set of 6-8 reps with no leg support. From there, work on performing multiple, unsupported sets (still with 40-45 second breaks between sets).
But, if you're currently only able to do 3 reps a set, and only one set an hour, then, your muscles aren't getting the chance to break down enough in order to gain strength over time, and you'll kind of be spinning your wheels (not making much of any progress).
And that's the difference between 10 sets of 3 reps, and 3 sets of 10 reps -- with the latter (3 sets of 10 reps), you're actually breaking down your muscles enough (causing micro-tears), which in turn promotes increased muscle strength/mass after recovery.
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Just remember: when doing these pull ups, make sure you're fully extending your arms when going down (i.e., make sure you're utilizing a full range of motion). This will significantly help you increase strength in a much shorter amount of time; and, it's the proper way of doing a pull up.
Good luck, and stick with it!