Is it normal for me to feel this way?

Its perfectly normal to feel jealous of your siblings, its the way thing are. But you are obviously very bright, with the studies you are doing, and you will come into your own, in your own time. It may feel like all the attention is on your sister, but i bet she feels a bit like that about you. Dont worry about these feelings they are perfectly natural. You just concentrate on what our doing, and be happy with what you have accomplished!:)