There are many variations of the pullup. So find one you can do and then work your way up as you get stronger. Practice it every week until you hit a certain number of sets and reps. When you hit that, you can move on to a slightly harder variation. Eventually you will work up to band assisted pullups. If that works for you, absolutely awesome.
The bottom line? Don't feel embarrassed if you can't do pullups yet. The band assisted pullup is an exercise you can eventually get to I'm sure. I myself I often come back to it, as I did today at the end of my workout.
The human body is built to hang and climb. If you can't do a pullup you probably have just never been taught how to build up to it!