Answering the original question: assuming the stuff doesn’t flake off easily or contain asbestos, it’s not hard to do yourself. I did one just two weeks ago.
Make sure you get ceiling paint; the formulation is different, which means it dries faster and stays properly adhered to a horizontal surface without pooling or dripping or whatnot. For your rollers, the covers you need are foam, at least 3/4" thick, preferably 1" to 1-1/2" thick. Look for ones that say “slit foam”. The foam is slit many times around the circumference of the roller cover, which allows the roller to slip around all the popcorny bits and paint them completely.
When you’re painting, you’ll probably have to apply a lot of pressure to get full coverage. Either get a very long roller pole, or expect your shoulders and lats to hurt a lot the next day.