How can I make this better?

Seems pretty good, but I don't think it's necessary to say " 'Ahhh!' The girls screamed..." Because you said the girls screamed, or if you don't want to get rid of "Ahhh!" then make it a little more of a screech, because Ahhh! sounds more masculine. and last thing, I thought there was only one monster, it might have been a typo, but you said "The monsters stared at the tent with its mive..." but that's just my opinion. Good luck with this! =D