It's easy enough for a long-haired girl to just walk into a shop with wigs, and try on some short-haired ones, to get a decent idea before taking the plunge.
Yes, you can get all the hair under a short-haired wig... quite easily. (Think of how easily it gets into a shower cap)
If you have long hair and are THINKING about cutting it short, here are some things to think about:
* Having had long hair all my life except for a 2-3 year period, I can tell you that you will be VERY conscious of yr face. So, just make sure that you LOVE yr face, or are at least very comfortable with it.
* Short hair requires MUCH more daily maintenance/upkeep -- in the "getting ready to go out the door" sense, not the washing sense -- than long hair does.
Long hair is super duper easy. Apart from washing and drying, I spend about 45 seconds/day on hair care -- brush out and go.
If it's a bad hair day, boom, 4 more seconds and it's in a pony. Still under a minute, and, good enough for even the most professional of settings.
* Keeping long hair out of my face at the gym is trivial.
Ponytails (and/or pigtails if it's leg day) are incapable of stabbing me in the eyes at the worst possible time, which shorter hair does all too easily.
I make most of my living in fitness, so, this is not a small issue.
* Long hair is much more versatile. You can... DO so much stuff with it.
Ponytails, high ponytails, curls, pigtails, all manner of updo's, crimps, bla bla bla bla. All the things.
You got short hair, you got... well, that one short haircut. Hope you like it. LOL
Not to mention, ironically, it's easier to wear a short-hair wig with long hair, than the other way around. Gathering up long hair underneath a short-hair wig is, again, super duper easy. Gathering up hair that's too short for a ponytail, to fit under a longer wig? Ahahahahahhaha. Nope.
* Finally, if you cut yr hair short and then grow it back out long, ohhhh girl the awkward phase. It lasts for many many months, during which you'll re-acquaint yrself intimately with those plastic headbands, like yr 10 years old all over again. LOL And you'll have to put yr hair up in those weird half-ponytails with the bobby pins in front for workouts.
Still, I say go for it. Yolo, and all that.
My husband would approve, too. He LOVES short hair on women, and makes the (entirely valid) point that a beautiful face looks all that much more beautiful with less hair to get in the way of the side profile.