It helps to like to create things. It doesn't really matter what. But you like to build a thing.
And you like understand a thing and know how it works. Curiosity.
It also helps to be comfortable with math. You don't have to be great at it, you have plenty of time to learn more. But you should be comfortable with the idea that you would spend a lot of time doing math.
I see you're in Pittsburgh, I went to Carnegie Mellon University in Pittsburgh. In the engineering college, they have:
Biomedical Engineering - I initially thought of being a biomedical engineering and an electrical engineer, because I wanted to build prosthetics. If you really like chemistry or biology, this could be interesting for you.
Chemical Engineering - I don't know a lot about ChemE. But in broad strokes, a ChemE takes some research a scientist did in a lab in a test-tube, and figures out how to do it in a giant processing plant.
Civil Engineering - I know even less about CivE. But common examples would be building bridges/buildings/dams/etc. As a CivE, you might need to make sure whatever being built is environmentally efficient/compliment. Or, of course, is structurally sound.
Mechanical Engineering - Essentially building things that move. Robotics is a cool thing that comes to mind when I think of mechanical engineering. Or maybe designing a new engine. Or a giant ship. Or a refrigerator. Or a vending machine that quickly creates ice cream as you wait.
Electrical & Computer Engineering - This is what I did.
You could work on radio-communications, like in an aircraft, or wifi, or cellphones.
Or build new computer circuitry, like designing a CPU.
Or you could be working on embedded systems, the computers that are in things like ovens/cars/thermostats/elevators/pretty much everywhere except personal computers.
Or you could work on the operating system for the iPhone.
Material Science & Engineering: I also don't know a lot about this one. But basically, studying / and creating new materials. Like the skin of a stealth airplane that absorbs radio waves. Or new alloys to jet engines. Or armor, like kevlar. The wikipedia article for Material Science has a cool list of "Emerging Technologies" with examples like this.
It is not uncommon, but not easy or necessary, to study two different engineerings. But no matter what, each thing you learn in engineering is like gaining a new tool for your tool belt, which you're use to build/inspect
In a lot of engineering schools, it helps to have an idea of what kind of engineering you are interested in. But they often don't let you pick until after you've taken a basic course in at least two, and it's common to change your mind in this time.
I have an electrical engineer friend who worked on designing iMac circuitry.
I have an electrical engineer friend who worked on blimps that looked for incoming missiles.
I have a mechanical engineer friend who worked on construction vehicles.
I have many computer engineering friends who work in software..
A common flow of work is:
- Someone tells you what they need (you get the requirements)
- You figure out how to build/improve something so it does what they want it to do.
- You build it
- You prove it does what they want it to do
- You make sure it continues to work
In many things, you prove it does what you want it to do before you build it. You wouldn't want to build a bridge without having some computer model to show that it won't fall down in high winds. But sometimes this doesn't work out at planned. https://en.wikipedia.org/wiki/Citigroup_Center#Engineering_crisis_of_1978