While I don't think a diagnosis for your daughter is the most important thing, I would like this opportunity to share what I learned after my husband was diagnosed with an OCD Spectrum Disorder in 2002. Talking to someone about her stressors is an excellent starting point if her tics become a bigger part of her life.
Anxiety in anyone can be alleviated by a number of things. We may tap our foot, count to ten in our heads, walk around the block before a job interview, write in our journals...the list is endless. After my husband was diagnosed with OCD, I learned that it is a spectrum disorder, and that some people's stress alleviating activities have a bigger impact on their daily lives. Think running back into the house to get the hall light (even though it is already off) versus not leaving the house until every light switch has been turned off and on six times.
Medication in my opinion should come after behaviorial modification therapy. When behaviors are not yet having a impact on her life, it is easier to talk about them and help her come up with more typical coping mechanisms. Because OCD is less a chemical imbalance than a behaviorial issue, it is one of the only ones that can be worked out with behavioral therapy alone. Medication can be avoided sometimes, or at least end up the best med at the optimum dosage.
I hope this helps, but all in all, she sounds like a wonderful girl and the advice to leave well enough alone is perhaps the most valuable of all.