If you’re still starting out, when you begin a new project don’t worry about grid systems at all. The design that you have in mind should have some sort of grid in it anyways, just start building it!
There’s so much hype about boiler plates and grid systems that I think people starting in the industry get a little lost in thinking that they *have* to pick one of them. You don’t! Perhaps some people would argue that they help people learn, I disagree: I think they only help people learn that particular system.