The biggest thing I can advise that hasn't already been mentioned, is to take it gently when at the range for the first time or two. This isn't so much for the OP, but maybe for anyone who may read this in the future.
Too many times I see parents take their kids to a range that has a lot of people at it. The parent already has high hopes for their kids to perform well, this is only amplified around other people. The kids naturally want to please their parents too, so they are already nervous a lot of the time. Again, this is worse if others are around. This combination makes for a parent who quickly become irritated/excited when the child makes a mistake (which is likely) and a child who may be a little sensitive to such reaction. It's imperative to remain calm. If they make a mistake, don't over react. Simply correct it in a calm manner, and explain to them how it was wrong (if they don't already know) or what they could have done better to improve. Getting excited, yelling, etc. often turns kids off from the shooting experience. You don't want this for their first few times shooting.
THIS!!
I took my daughter to Atterbury on a Friday right after school in May. Range was EMPTY! We were only one there for a half hour. Then some guys showed up with a Mosin at the other end. Scared the living bejeezus out of her. She was ready to go home scared. I told her it was fine and urged her to carry on. Then some guys(on here actually) showed up with a 45 Colt and a 454 Casull and fired about 3 stalls over. We BOTH jumped when they went off but finally got in the hang of it. By the time she left it didn't bother her to the point of tears. She's been fine ever since.