Your sister is a fanatic for chemistry, so you may feel like that territory is already staked. I understand. That’s not a good reason to eschew chemistry, but I get it.

Chemistry is challenging for many people. It requires a lot of memorization and it’s hard for most teachers to explain clearly. Maybe it’s not most teachers, but every one of the three I had. (My high school chemistry teacher was continually very drunk, but that’s no excuse).
The reason you should care about chemistry is that it is all around you. You are built of chemistry, moving around in a world that is also built of chemistry. Everything inside and out–more chemistry. That rough spot on the roof of your mouth that’s bugging you? It is part of you and it was once star-stuff.
Imagine a fish who couldn’t be bothered to learn about water, meanwhile other fish were busy building all sorts of new water and tinkering around with it. That is one foolish fish.
If you need even more incentive to learn what you’re swimming in, you could listen to Oliver Sacks explain why and how he loves chemistry. Go ahead. I’ll wait right here. (You might want to skip to 2:30 in the recording if you are in a hurry).
I think we should follow his example and examine one element for each birthday. I have just the tool for you!!
Happy Birthdays, every time!!
Love,
yermom