I'm kind of in your boat, 5'4 & 120 lb. I have a stable full of folders, so here's what I found out.

You pay a price for foldability in terms of cost, weight, "finickiness" of components, and sometimes oddball parts not easily obtained locally. Dahon is notorious for this in my experience. Not unusual for folks to wait months for replacement parts, and when we're talking main frame hinge, that bike ain't goin' nowhere until the part comes in.

So to answer your question: If your primarty concern is being able to fold it up to take on a bus when racks are available, I wouldn't. I'd keep your 26" bike and deal with the lifting onto the rack thing.

Now if you're living in a tight space, or maybe in a walkup with narrow twisty stairs, makes more sense. Or if you're doing serious multimodal commuting with several stops each day, but even then, folding/unfolding can become quite the chore. This is where the Brompton comes in so handy: 23 x 23 x 11" folded, and I can fold/unfold in about 30 sec.

Don