Sounds like you are expecting to have a saleable calf and get milk to drink and make cheese. Right?
Marketing a half full sized, half mini something, part beef, part dairy might be difficult. Are you thinking you'll be selling a beef type animal? With very little information to go on, I'm going to stick my neck way out and say the guy you got her from has little idea what breed combination she is. If she is more Jersey than you were told, then birth weight becomes critical. But breeding her to a Jersey, when she actually is quarter or half Holstein, gets you a calf that is way smaller than if you'd bred to an Angus.
A little of this breed and a little of that breed destroys the individual breed standard that breed associations developed over hundreds of years. There is a good degree of predictability in that.
Should I assume that you know what a Free Martin is and that she isn't?
The mini or low line cattle is ,IMHO, just a fad. Money can be made if you are willing to do a bunch of marketing. But even within that audience, it is either a tiny cow or not. I don't see any demand for half mini-Hereford, quarter Angus, quarter some combination of a milk breed.
Many first timers kill their first calf. Too much milk. No electrolytes on hand. Scours tablets not given early enough. Untreated pneumonia. It is a learning curve that the calf pays for with her life.
Angus do not produce a ton of milk. Angus generally are harder to milk. How disappointed would you be if you could only get a quart of milk, twice a day? You have time for that? I'd get the milking stanchion set up and feed her in it every day. There is no good way to know if her milk production will follow the Holstein (if that breed is in there at all) DNA or the Dexter/Brown Swiss/Jersey/whatever DNA.
A new calf in October in Indiana is fine. But a two month old calf in December might be a bit harder. A four month old baby in the bone chilling February snow storms will require some good weather proof housing.
Sound like you are having a blast. It may not matter the value of the calf. It may not matter how much time you spend coaxing a bit of milk from your Daisy May. What matters is that you are enjoying this adventure.