I love your enthusiasm to jump straight into the deep end I do, it's often the best way to learn. I too have that problem. My advice to you is to step back a bit, build a small project based on your idea and add small bits to it overtime. Build up your own knowledge base of how Construct works and when your ready to go ahead with such a mammoth task, you'll know.
You will also most certainly need to purchase the Construct3 license in order to build this huge MMO game that you plan on doing.
I would most certainly join you in this project but my knowledge of this engine severely lacks. I have the tendancy to start building a game, move onto the next, scrap it and repeat. This time I'm going to work on just the one game and then release.
If you jump straight into this project of yours, it's going to be a full time job. I'm talking graphics, sounds, programming, planning, marketing, playtesting, animating as well as whatever real life tasks you have around you. You need a team for this type of project, I would volunteer but first you need a good grasp of Construct.