Welcome! I'm intrigued that you have a miniature Hereford, because my sister would get a miniature Jersey, but they are so expensive and there's a huge waiting list. I'm curious if that's the same for miniature beef breeds like Hereford as well. How did you acquire your cute little heifer? We purchase a lot of raw milk every week, so she wanted to milk her own cow, but thought a full-sized Jersey my be a bit much for us!
As the others mentioned I would strongly suggest AI. Having been very inexperienced myself with cattle birthing when I started breeding, it was very assuring to know that a bull that is being collected for semen is going to most likely be a high-quality bull with low birth weights, etc. I've had awesome results from AI'ed heifers. They dropped their first calf easily.
It will be interesting to follow Clementine's story!