I agree, at least a year of regular classes but depending on you and your dog towards the end of the year, start going to funmatches and entering. If you are serious, get your own weaves, it will take forever to train them if you are only going to class once a week, even twice a week.
A good rule of thumb for when to start competing is when you and your dog can successfully handle courses at least one level above the level that you start at. If your going to play in AAC that is really important, because its easy to pick up legs in Starters and Title, the game changes once you get into Advanced. And people often bottle neck in Advanced.
In Starters, refusals don't count on weaves or contacts but do for everything else. Once you are in Advanced, all refusals count. So if your dog misses a weave entry or pops you have just joined the 5 fault club which means no Q.
I know someone that Titled out of Starters quickly but since then for 3 YEARS has not been able to pick up 1 Q, let alone Title. Thats a lot of money in entry fees and training, not to mention the frustration for both them.
Yes, it is suppose to fun and not about Q'ing and Titling but I think people and their dogs can only take so much of near misses before they give up and quit.
I have a dog that is fear aggressive/reactive and it hasn't stopped us from trialing. Having said that he is also not a dog to leave me to engage another dog, he only reacted if they got to close and within his comfort zone, then he lunged, snarling and snapping, looking and sounding like the biggest bad a$$ going but it was only show. Although he did nip a dog once, his biggest fear, big and black and too close with me not with him.
I worked on his reactivity, he can now walk through a tight crowd of strange dogs and not react. I also manage our surrounds or at the very least be very aware of the dogs around us, because its not the reactive dogs you have to be worried about for the most part..........its the dogs that are friendly that are often rude about greetings and owners that are not paying attention to their dogs bc their dogs are friendly.