Need some help on how to start my project (important)

Hello!

So firstly I'm absolutly new in here so I'm not sure if I'm opening this in the right section... Secondly my english is really basic and not perfect so there will find some grammer mistakes while you reading this... Thirdly I'm also completly new to Unity, I never programmed/made/developed a game before and I'm not really familiar with the programming languages too, I learnt C++ in my school but that was just some really basic programming, doing some simple tasks in CodeBlocks and dispalying it on the Console, so yeah I just don't really have that much experience with this but it doesn't matter because I need to make my project in Java...

So now you may I ask, what is the thing you need help? Well I need in a lot, but mainly just a direction to where to start...

So here is the story:

I'm 18 years old and I'm just finishing school and I'm in a Math-Informatic class where we need to give a project what we created but it can be a HTML project, a simpel CMD project with Codeblocks, a Visual C project and a lot of thigns what can be easy but I was so ambitious that I can make a game because I always loved playing games and making (I mean I never made a game, just I always enjoyed editing in a game own editor field) so I though I can make a simple game in Unity because I always adore how easy and simple the Unity editor can be, I thought I can just simply watch a tutorial on YouTube and make something like that with changing the textures and things like this (I actually started to make an own Flappy Bird called Blue Bird (link) but I just copied what the guy did on the tutorial, just downloaded some pictures from the web and messed a little bit with the physics, so I just don't really have an expereince with that...

So we have to fill a form where we need to write in what programming language we are working and what will be the project's name, so I filled out that I'm working in Java because even I know a little bit of C I'm still not thinking that I will have any advantage over with Java and the the thing is that all the YouTube tutorial are made in Java so I'm not really having an option I think, I know a lot of Unity editors prefer C, I red a lot of thread about that, but I hope Java is not that different and I can make what I would want... The project name is Logical Puzzel, so basically the idea was a 3D game where we are in some chambers like in the game Portal (demonstration picture, an other one) because the map design would be really simple and I also like this kind of art design what Portal has, so I though it will be a similar game but without portals, it will be heavly relied on swithes and buttons, so there will be 3 chambers (because I don't want to make it that long) and the player need to figure out how he can get throught, basically I want something what makes the player thinking how he can get throught but still not be that hard, there can be some moveable boxes and balls, things like portal but only with the use of buttons,switches and things like that...

The other thing is while I love the Unity editor I'm still not sure that this is the right one for the project, in my class 2 students work on a game too and they are working in Greenfoot, is it better for a game like this or not?

And my final question and maybe the most unpleasant thing is that I just had a lot of work in the last month and I absolutly forgeted this and the deadline is the 4th of May, and I will not be home on the 27th of April - 3th of May, so basically after we fly to Italy for a vacation I can't do it after we get back because next day we need to give the project to my teacher... So yeah basically I only have 5 days with this day and my final question is do you think I can make this on 5 days, or do you think I should do something more simple because there is no restriction on should we do it on 2D or 3D? I know 2D is easier just I'm not having an idea how should I do it..

I'm really thankfull who have the time to write here and help me because I'm absolutly shocked and panicked that I forgeted this important project... I hope I can finish it somehow, even if it will not be that good, but it's not that important, just I need to make something...

Thankyou!