@misfitmorgan has hit on the basic points. Here's a little more of my opinion after 40 + years working with and in the dairy industry. Jerseys will make the best "homestead" cow of the 5 main breeds of dairy animals. Jersey, guernsey & ayshire (about the same), holstein, brown swiss; smallest to biggest. They will be the smallest, as she said, in the 800 to 1100 lb size. Brown swiss are the Biggest. The cows will average out at 1600 + lbs at 4 yrs and older. They are also a very quiet breed but are VERY stubborn. They also have some more problems getting bred and mature slower. I have had some. Not for the beginner to deal with the stubborn independent attitudes. If they don't want to do it THEY WON"T. Holsteins are the next biggest, make the most milk. There are ayshires, which are a bit more high strung but not bad, and then there are Guernseys. My favorite, but hard to get any good ones nowadays and hard to breed. The commercial dairy industry took the "old family cow" that the guernsey really was, and tried to breed it for more milk, made them more frail and there are issues.
Then there are the Dutch Belted, and Linebacks, which are both nice dairy types. The linebacks are more of a dual purpose as are Milking shorthorns. Then you get to the smaller "dual purpose breeds. Dexters are smaller, but not much more than a jersey. Also Kerrys, but they are more high strung. And there are alot of other breeds that are being used in the dairy industry for farms that are into grazing, like swedish reds, normande, & others.
ABSOLUTELY UNDER NO CONDITION should you breed a jersey cow to a brown swiss. The swiss are too big boned, and it is a recipe for a disaster.
You cannot keep 2 bulls to breeding age together; and you should not be keeping a bull of any dairy breed with children around. They are more aggressive than most beef bulls. And no one should keep a beef bull with only a couple of cows to breed either. They will get bored, having done their job and you are looking for a problem to happen.
Swiss eat 2x what a jersey will eat. Not economical for a small operation unless you have alot of pasture.
Swiss also will grow alot more frame and bone before they put on weight (meat). Take longer to mature.
You need to use AI, or a borrowed bull, or take the cow in heat to a farmer that has a bull, for a day, so she can get bred. Problem with that, many are getting to the point of closed herds to stop any infectious diseases. Some places will rent/lease a bull, but they are also picky about who, what, where, when, why, and health issues. AI is really the only sensible way to go for the small farmer, and if you have a stall/stanchion/head catch that the cow comes into to be milked, then she can be caught up to be bred.
You would be better off just outright selling a heifer calf to maybe someone else who wants a "family, homestead" cow. And if it is a beef cross with your dairy cow, it will make a good beef whether it is a heifer or a bull calf. You need to get the bull calf(calves) banded as babies, let them grow up as steers and eat or sell them. The heifers will start to come in heat from 8-15 months all depending on the breed. It will be annoying enough to deal with them and even the steers will be jumping (riding) them. A young bull will have little/NO respect for fences, people or anything else. You will get hurt, plain and simple; and a heifer might get bred back way too young, then if you don't abort her, it could kill her to calve when she is too small/young.
This is not to be critical, because I am all too aware of being very busy and trying to raise a child as a single parent. Your son's eating habits are going to be a reflection of yours, so if you do not try to have some sort of regular, normal, eating habits, he will not develop good eating habits either. Before you try to raise a bunch of animals, you might be better off buying a quarter or half beef from someone and get into a routine of making regular meals to establish a pattern of eating. I worked 2 jobs and had to deal with an ex and still we had at least one regular meal a day, and my son developed some decent eating habits. Raise a garden and eat what you produce. You need to provide the example of eating good balanced meals and not snacking on leftovers. It's a habit he will have the rest of his life.