We've all been there. I soldered the wrong end on the battery then use come channel locks to seat the plastic shroud. It would have been find but I had the male end on the battery. That was a surprise.
Putting a connector on a battery is not very hard, make sure you only have one lead exposed at a time. If both positive and negative are exposed they can short and that gets exciting.
Also DO NOT CUT BOTH LEADs AT ONCE. If you cut through both leads at the same time you will be connecting them...