I am also going to say CSS first. Doesn't even matter what you're learning, you need to understand the fundamentals.
I get really frustrated when so many tutorials for complete beginners throw a framework behemoth like bootstrap into the mix. I understand why they do it, but i would suggest that you actually stay away from frameworks untill you can basically achieve what you want with just pure css. This doesn't only apply to CSS, nor even just programming/design.
Then if you feel you need to speed things up you can either reach for a framework, or better yet, while getting a firm grasp on the fundamentals, you end up with kind of a 'framework' of your own.