It's a very ambitious project for someone who as you said "am not an electronic guy... just good enough to put myself in troubles! ".
Circuit design and PCB layout is not something you learn overnight or can do in one day.
I will often spend a week or two reading datasheets, selecting parts, and drawing schematics. Sometimes doing spice simulations to make sure it has a good chance of working. Then maybe another week or two doing the layout, often going through several revisions "on paper" before I get something I like.
Proper thermal design is often completely ignored by many and often leads to premature board failure. It not only applies to the ICs but to all active and passive components as well.
I would not have the time to review your design to make sure that it has a good chance of working with the first iteration.