If you still want to work with these girls, but you want to "catch up" to the level you think they're at, try working on your own as well as working with them. Learning new things, be it learning a new religion or riding a bicycle, takes time. Some people will catch on faster than others. Have you considered working with an experience mentor? Most teachers, Wiccan or otherwise, understand that within a group dynamic, there will be people that sail through lessons, while others take a little longer to get to shore, so to speak. A good teacher will know how to keep things going so that someone who isn't learning as fast as the others, doesn't feel left behind.
I think that a true witch is someone who is serious about being a witch. They do their best to lead good lives and incorporate their magickal beliefs into the mundane side of their lives. You won't be able to pick a witch out of a crowd just by looking at them. If you do spot someone in the crowd that has on lots of black, is loaded down with large stone jewelry and has five or more pentagram necklaces, chances are you have found a fake witch. If someone says they are a witch just to anger their parents, or to seem cool, or to try to scare just about anyone, they aren't a witch at all, they're more like a sad version of a cos-player.
Traits like telepathy and empathy aren't a prerequisite for becoming a witch. Everyone has these abilities to a degree, but most people go through life without ever experiences these gifts. It does seem like many witches are quite talented in these areas, but a lot of times, it's because their practices help amplify these abilities. Think of psychic abilities as muscles: the more you exercise them and use them, the better they perform.
To sum it all up: practice makes perfect. Keep striving to learn new things, no matter how long you've been a witch. Keep reading and keep casting circles. You'll get the hang of it. If these girls try to bring you down by telling you you're not go enough, leave them at the curb.
