I joined the md ibra 2 years ago I absolutely love it. It was a great place to start for me because we didn't have the speed and we are still a work in progress. I love the ibra because I feel as though everyone helps each other out and it's almost a close family since it's a decent size group. 

Starting out i was told until I get a little more speed and place a little better then maybe join the nbha. We have improved in the last 3 years racing and especially the last 2 years running with the ibra but we are still working on a few things and we are still in the 19 range so until that number gets lower I will probably stick with ibra but I would love to try the nbha when I am ready.

If I were you I would check out what is more popular in the area you are going to and see arenas to see what the ground and set up is. Most of the time you don't have to be a member of either to run at their approved shows. Now if you are interested in getting points and running at national shows then I would decide that by where and when those shows are and how many shows you might have to go to to get there. There might be local series or organizations that are just as good.

Since you are just starting out, I would say look at the barrel races that are closest to you. I am sure points for either group start in January so everyone would be ahead of you if you were to join now. Don't know about IBRA but NBHA does not require you to be a member to run so until the end of this year just go learn the ropes and meet people. In January if you want to join one or both, join then. Edited to add that you can join any NBHA district that you want to. There was not an active district near me in TX so I joined one in LA. That group disbanded and the LA barrel races are about 150 miles away.