Nope, doesn't matter. I got to wear scrubs pants (I know, impressive, right?) with what was supposed to be a scrub jacket. But the only size the volunteer coordinator ordered was unisex large. Well, I'm about 5'2", 110 pounds...didn't quite fit and the coordinator didn't care, so I ditched the top. Even with the 'volunteer uniform,' which a friend of mine actually wore all of (pants + jacket), we still got treated pretty badly. People kept asking me which of the area high schools I go to. When the charge nurse asked "Hey, where's the little volunteer?" that was kind of it for me.
Although, I did think it was kind of funny...a lot of the volunteers go to the local CC and are nursing students, so when I commented that I go to the 4-year college and want to go to med school, everyone was rather impressed
Long and short of it, I've wanted to take EMT since I was 15 years old and my parents wouldn't let me. Now that I'm old enough that they really can't tell me what to do, I'm taking a crash course this summer and that way, I can do something I actually enjoy.