I'm currently booking out until August for board and train dogs and that is not unusual for good trainers in the area.
If you have a puppy who is 3 months old, a prime board and train age is 7-8 months so you might as well get them on the calendar with your favorite trainer (me or otherwise) early.
And most importantly:
If you're dealing with a behavior problem and you're waiting to get to your breaking point - don't! The problem you're experiencing right now WILL get worse if you don't make changes. There's nothing more frustrating than getting to the the ultimate point of frustration, finally picking up the phone and being told you need to wait 2-4 months to get the training you actually want.