The first plucking of a junior French angora should occur at around 4.5 to 5 months. (So hang on there, Emmie!) There are some breeders who plan in advance to breed their rabbits so that their juniors will be in prime condition, about 4.5 months of age, for the big shows. This seems like a really good idea to me, and I will be using it in the future. If the breeders are showing them at their best at 4.5 months, this suggests that the prime time for the first plucking is 4.5 to 5 months.
I plucked my first rabbits much earlier than I should have. Knowing when to pluck is, I think, of great importance, so that the rabbits won't get wool block and so that I can have them in good condition for show. Also, don't become so afraid of wool block that you are plucking your rabbits too early. Just make sure that they get their papaya pills or cubes and plenty of hay and fresh water.
A blower, though a bit pricey, is an invaluable investment. This is because your angoras will be able to keep their wool in longer, and it will keep the coat from webbing and matting. And blowers do not remove as much wool as a comb, so your rabbit has a much denser coat for show. A blower should be used once a week for just a few minutes, and definitely right before going to the show table.