I would suggest taking your time before hopping into this right away. Although, it sounds great and inexpensive, it can turn into a nightmare very quickly!
You'll want to make sure you set up a Google folder with all of your information, along with log-ins, passwords and anything else you think is pertinent to their position.
You'll also need to figure out timezones, holidays and their work schedule and how you can onboard them.
From there you'll need an emergency "escape" plan. Also, keep in mind this is NOT an employee and you'll want to make sure there's some type of agreement with them in place, so they can train the next VA in case they decide to quit or leave.
If this person suddenly vanishes, how will you get your info back, and make sure you're not locked out of any accounts. I only speak from deep experience with this exact topic and can pass along some of those nightmare stories if you'd like to hear them.