There is no defined criteria for Mount Everest climbers, still there are some things one should know.
The first thing you’ll need is to be over 16 on the Nepali side and over 18 on the Tibetan side. The second thing you’ll need is a lot of money.
You need to be in exceptionally good shape and have a great deal of experience in extreme mountain climbing if you want to have a realistic chance at actually making it to the top. You will file additional papers and have a half an hour briefing with the minister or his associates.
You will have to meet local a Trekking Agency as they will provide you with the papers and get you the required appointments.