You won't like the "wow factor" if the plane crashes into the school, someone's car, or even worse a person.
It's nice that you like gas, but you should abandon the idea of trying to fly a glow powered train at a school during the day in front of people. It's not safe and I'd be surprised if any teacher would permit it unless the facilities were right and you were able to demonstrate adequate proficiency before hand. With less than a month to learn, you're not going to get to that point. Something to think about is that an accident of this type is what leads to more laws and regulations against flying. Don't try something stupid and mess things up for the rest of us.

Additionally, setting up and operating a glow engine adds to the complexity of the project. If you're really going to accomplish this in the given time, you've got to go the easiest route. IMO, an electric trainer would be significantly easier to assemble and get flying than a glow trainer. Their significantly slower speed makes them easier to learn on, allows you to fly in a smaller space, and increases the chances that you could get good enough to even think about a demo flight. Said demo flight should not even be attempted in front of a crowd unless you can prove before hand that you are in FULL CONTROL of the plane.

My suggestion that you may be able to pull this off was only for a small, slow, electric trainer. It was also based on the (perhaps overly optimistic) assumption that you are mature, a quick learner, and able to understand and follow directions (both for assembling the plane, and of the person teaching you). Change any of these assumptions and you most likely cannot get to the point of doing the demo flight.

So, the bottom line is if you think you are going to try to learn enough to do the demo, go electric. Even if you don't get to the point of being safe enough to do a demo, you have more than enough material to complete the project. If you prefer glow, find an instructor, build a glow trainer, document the building process, and have someone tape some of your lessons (at a proper flying field, not the school yard). You could also go the tape route with an electric and eliminate any risk of causing problems at school. Present the project to the class in the form of an in class screening of the film followed by showing them how the plane works. Obviously, you don't want to be starting the engine during the in class demo, but if you went electric, you could at least demonstrate turning on the motor.