first off...
grats on taking courage and doing something you wanted to.
now for the rest..
you all seems to ignore what she actually wrote... it was her first time.... (not first zoo, but first time), probably the reason it was so painful for her...
its not about "try again soon" more like
this things happen and explain that.
soph, over time those sensations will change and you will get accomodated to the feeling (been with a dog or with a guy) , its absolutly nice that you have done it with your dog as that was what you wanted to, but animals are rouger than humans, so im not surprised your first time had gone that way... BUT its not always like that, its all about experience mixed with other things.
just relax, let your body regain its strenght and take your time to accomodate to the situations...
you do not need to jump to it again soon, but the more you try slowly the better it will get (with ANYONE) lol
now you know what to expect, what you can like and what you will not... take that in mind and "practice"

(yo do not need to practice with the dog but get ready for when it happens again)
not sure if im clear
have an amazing weekend!