It is hard for anyone to correctly tell you what is a good holster for YOU. That is like picking any other personal item, it depends a lot on personal choice, what works for one guy will be absolutely nonfunctional for another, depending on many factors. To make matters worse, we all have our favorites that work for us, so we tend to recommend them with wild enthusiasm and forget what is stated in my first sentence. Rather than give you a particular model, I would just say to look and see what the good shooters are using. Benefit from their experience. Second, don't cheap out. Most everyone on this board will tell you that a cheap holster is worse than no holster, as you will be out money learning that you should have bought something else.
Watch a match first. Learn to safely handle, load, unload, holster, and draw your gun. I have seen some new guys make some very dangerous mistakes the first few times...pointing guns at folks, finger on trigger during administrative handling leading to negligent discharges, poor muzzle discipline. Remember, don't hurry, let the SO direct you through the activity.
The payoff is skill, knowledge, and big fun.
Sometimes...days are just something you get through.