I would subdivide that 100 acre pasture and rotationally graze different areas one at a time. Hopefully you have good perimeter fences to start with. If you are not familiar with them, learn about electric fencing.
At weaning time, separate the calves off into one section with a good fence between the cows/bull and the calves. There should be an electric wire on standoffs on the calf side. This is called fenceline weaning. About a month before the cows calve and about 3 months after weaning, I sort the cows/heifers away from the bull and put all the steer calves on the bull side. This leaves you with all the females on one side of the fence and the bull and steers on the other.
As mentioned above, your biggest problem will be any females or another bull in an adjacent pasture. As a fellow beginner I was very concerned about this also when my neighbor had a big old rent-a-bull on his side of an older barb wire fence along with my younger bull on my side of our shared fence.
I fixed the fence/tightened wires as best I could and put up very hot (6 joule) electric wires on 5" plastic standoffs on BOTH sides of this old fence and it was the only thing that would control these bulls as far as I can see. The older one especially would come up and stomp and bellow but neither of them would get too close to the hot wire. If it was just barb I'm sure it would not have kept them apart.
Getting started with 35 head or so (or really any number!) you really need to look at good fences, good water and some sort of working/sorting facility, in my opinion.
I do not have the facilities to "pull the bull", nor am I finding you need to. If you have a good bull he will do his job in one or two 21 day cycles at most. Make sure you have a bull with a recent BSE. Leave him in.
My system is that when the first calf hits the ground (about 283 days after bull-in date) a clock starts ticking. At this point there is nothing you can do but wait for calves, however any cow not calving within 45 days of when the first one hits the ground goes for a trailer ride with her calf to be sold as a pair or 3-for-1. No exceptions. This keeps your herd fertile and your calving season tight. I want most calves born in a 21 day period (first cycle) but with 35 heifers and one bull he may need two cycles to hit them all.
And 283 days of when you want calving to begin (April 1 here) you put the bull and any steers still around back in with the cows and calves and they are one big happy family until the process starts all over again at weaning.
I would suggest you consider rotational grazing of that one pasture. With this system , however you really just need one good hot fence down the middle to divide the pasture into two sections. Good luck.
Jim