Your height isn't a too big of a factor. Unless you are under 5'4". You can handle any crossbow up to a Ibex.(according to the excalibur website)

So the Vixen should be good for you,

I have a friend who is 5'5" and he can pull my Ibex with minimal effort, with a the rope c0cking aid obviously.

Despite that these crossbows have rather heavy drawing weights all the models under 200# seem to pull very smoothly, so if your using the right technique and have a c0cking aid, they are rather easy to pull once you get used to them. I find that the Vixen can be pulled by just about anyone who can get enough range of motion, generally as said on the excalibur website anybody over 5'. And with the rope c0cking aid it hardly feels like 150# and your only pulling for 13.5"

But the easiest/best thing may be to just go to the store and try pulling the vixen and some other models to see how it feels and pick the one you are comfortable with.