Congrats on finishing your first 3D game, and amazing job doing it alone! This game works great, I didn't notice any bugs in my time, and I like that you made sure the camera was clamped to the play area.
One piece of advice I'll give you is when you do jam games, especially if you're doing them alone, try to take a little time up front to find some sound effects you think might fit the game and implement them while you're making features! Sound is the most bang for your buck player feedback you can give and makes a huge difference, so getting them in early is the way to go. Even just a small sound when placing a turret would make the action feel better. These don't have to be the final sound effects, just something temporary at least to help give more player feedback.
Awesome job, I look forward to seeing more from you!