I realize you just got a shotgun, but if you're really concerned, you could look into a shotgun with a detachable magazine. Though, now is certainly not the time to buy one, given the inflated prices, but it could be an option if you don't get comfortable with loading a tube-fed gun.
That said, I recommend just what others have said. Practice, practice, practice.
I like that tube-fed guns can be topped off as you go, but that's just me.