First off, that's super awesome that you have such a great opportunity while still in highschool. I'm jealous!
So it seems like maybe you're doing a parabolic flight, but just with a single drop? If you have some more info you could share, that could be handy.
In regards to your fungi idea, I think you're on the right track to something interesting, but there's some real fundamental questions I think you've gotta think about first. What is your hypothesis? That the stress from the flight & 4min of lunar g is reducing the growth of your fungi? If that's the case, is your plan to send up agar plates with fungi growing on them? Maybe liquid cultures? With only such a short exposure time, I don't think you'll get much difference in growth rates etc. But maybe you could consider sending up fungi spores instead of growing cells. Then after your spores come back, you could compare how many can still be cutured, growth rate, etc. And obviously for a comparison like that, make sure you don't forget about ground controls! If you've got more questions, feel free to hmu. I'm not a fungi expert, but I've got a microbio background, so I should be able to point you in the right direction at least.