Its meant to be there and can be asked anytime. Very few reports of being asked though.
The rules can change or be enforced anytime. Dont be surprised if it starts getting asked soon especially after the election.
A wise move is to keep it there and attend courses.
Remember bank accounts were closed and immigration dont want anything to do with it. 10,000 education visas where cancelled a few months back. There almost certainly will be a crackdown on it.
You can come to Thailand and prepare your documents but then you have to leave the country to where you are applying and stay there until approved.
Tourist visas are 60 days you can extend 30 days in country once.
If you mean visa exempt they are also 60 + 30 unless you come from one of the four countries that get 90 days visa exempt. Brazil is one. I can't remember the others.