I have only been AI'ing for 3 seasons now, so I'm not much more experienced than you. I would agree with the others who advise you not to get too frustrated. At first, it seems very difficult and if you don't have experience palpating (I didn't) it is hard to locate the cervix much less get the AI gun through it.
When I took the course, we went to a dairy and practiced on the cull cows. Only had about 8 head to practice on and we really didn't spend enough time practicing, but I did get the basics. There is a big difference between a mature dairy cow and a 15 month beef heifer (or cow for that matter). Unfortunately, the beef cows don't seem to stand still and often move when you know that you only have one more ring to pass through. Then it's essentially starting over.
The best piece of advice I can give for someone starting to AI is to build one of these.
http://www.allwestselectsires.com/breedingbox.asp
We built one this year and it turned breeding from a chore to a kinda fun experience. The last 2 years we were AI'ing in an old powder river squeeze chute. We had a homemade palpation cage which worked well enough, but the chute was so short that we would have to catch their head to be able to get behind them. Some would flat out lose it. Even some of the calmer cattle would move quite a bit. Add to that the fact that the tailgate would be dangerously close to your head and breeding was a lot of work.
With this box, we have done much better. The cows feed into it well and most have stood very still. We have a few that I could not get bred last year because they just would not stand still and we have run these in behind another cow and they actually stand better than cows in the front of the box. Also, it's just more comfortable with no bars or the squeeze in the way. I don't know if it's the box or just that I've AI'ed a few more, but I'd say the average time it is taking me to breed a cow has dropped from around 10 minutes to less than 5. I know I'd go broke as an AI tech, but it's ok for our operation.
We built the box 6' tall but otherwise the same as the design for around $300 and it has been well worth it. When this one wears out, we'll redo it with square tubing to make it sturdier, but this design works well.