Honestly, I'm one of those people who (if going from sedentary to working out) take a few months just to do a regular pushup. Even at my lightest and fittest (I was almost breezing through Insanity at one point back in 2012) I couldn't do a single pullup.
I added in weight training (sorta) last year, around may/june
I'm still using only about 8-9kg for my bicep curls, and about 8-9kg for a shoulder press with my adjustable dumbbells... I still squat with about 10kg per hand, tho I did get a barbell I can load up to about 30kg total... I feel like I'm still weak... fwiw I'm about 55kg atm, at 159cm, and I THINK I could do more with my lower body if my weights went higher than that... is my upper body "doomed" to be weak?