Hi M.---Unfortrunately these days high school sports are nearly as business like as college and the pros. Coaches are watching kids as they come through the ranks of local clubs and camps and usually have their teams selected before these kids ever reach high school. I know that seems cynical, but that's what I've experienced with my 3. Unless your child has amazing God given talent that they can't ignore, it's hard to break into the ranks as a child enters high school. The kids that make the teams have been practicing their sport since they were able to walk.
Now that's likely to be the case for most of the bigger, more popular sports, and that would include cheerleading and poms. One of my neighbors kids has been dancing all of her life. But, for the smaller, less popular sports she might have a chance. She can always choose to start getting coaching or personal 'training' so that she might better herself. She'll probably have to do that with private lessons, as again, most of these kids are on club teams off-season as to keep up with their sport. We did this with our son as we moved from Illinois to Clarkston when he started 9th grade. Clarkston has a premiere basketball program and my son had moderate skills. But his heart was not in working as hard as he needed to in order to be noticed above the kids the coaches already knew.
So there might be other things your daughter could get involved with outside of sports. There are tons of clubs and ways she can be part of a 'team'. Have her meet with her counselor to see what is available. Maybe she could get her athlete friends to join her in those. Oh, and be sure to look for intramural opportunities within her school. She might be able to learn some skills there. She might also be able to sign-up to be part of the support group of the pom team. In most of the sports, they have student trainers that help with equipment and keep stats for the teams.
Some kids just know what they want at an early age in life. Some have varied interests and particpate in a variety of activities that keep them from notice in any one activity. Stress to your daughter that she's not found her passion yet, and that there is time to do so.
I hope this has all made sense and helps in some way. You and your daughter made choices when she was younger and in part, those choices have lead you to where you are today. Not bad choices, but ones that did have an impact on her future. Good luck! D.