Start with YouTube -- "Crash Course Astronomy" and then "PBS space time". Both programs are very well done, and give fairly rigorous yet entertaining overviews to cosmology and the related physics (PBS space time is the more rigorous one). Crash course is great because it touches on almost all major cosmological phenomena. For some of the videos, you may want to rewatch certain parts for understanding, or supplement with some brief research via google.

This route provides a gentle, productive ramp as you make sure you really want to dive deep.

I've done that and, ideally, I'd like to now buy some college physics books. However, I may have to delay this next step for quite a while due to some other higher priority goals... We will see if I get back to it. There is too much interesting shit and important things to do in the world, heh.