I spent a lot of time searching and assembling a collection of links that I want to use for the project, without adding them into the game. Did I just use up all my time?

I’m gonna say no. Not that it’s up to me, but I was thinking about going to look for free assets before starting my timer.

Of course I have to come up with an idea first. An idea I want to do and think I can make semi-presentable in 3 hours of effort.

It's part of preparation. The 3 hours is for execution!