Welcome to the community, always nice to see fresh faces passionate about the game :D!!
You'll find out very quickly that there are enormous amount of groups who would love to have someone like yourself aligned with them, and because of that you have the power to really shop around and find a group that works best for you.
My advice take your time before deciding on a place to reside or group to become apart of and really just get to know people in the community and their groups, there will be no short of people wanting someone like yourself so use that to your advantage.
As far as you wanting to be a specific tribe the one thing you need to understand is no one is guaranteed the biome they want nor the tribe they want, so if someone promises you that, know its something that isn't really in their control at the moment, although they may want the same thing as you. However as someone like yourself who will be a gentry type player getting the tribe you want is a lot easier in comparison to someone who is a mayor, count, duke etc etc, since they are more restricted to the tribe(s) that is dominant of the area they will reside in. So even though you may not be in a northern brudvir biome, you could still potentially be brudvir, you may just not have a huge brudvir community around you.
Another option is to wait until domain selection when people will have a better idea of exactly where they will be located, and from there they can promise you a biome/tribe. hope this helps and once again welcome!
Some extra resources to find groups/communities
A good way to start is to check out the kingdoms and meet with the people inside of them, you will come into contact with MANY people and groups.