When you have Hep C (untreated) it is very difficult to pass it on sexually. Essentially straight sex does not do it. There are stacks of couples where one patient is positive and the other has remained negative for decades while normal sexual activity has gone on.
MSM (Men who have Sex with Men) seem to manage it occasionally, but that almost certainly relates to anal sex.
Once you are on treatment by 4 weeks you are almost invariably (80% chance) undetectable and 99.9% certain to have next to no viral load so the risk of sexual transmission, which was close to zero to start with, is not even closer to zero.
So the basic answer to your questions is no, you are very very unlikely to transmit it.
On the pragmatic front, in new relationships, you are given a "blob" of - largely undeserved - trust. That trust is yours to lose as much as it is yours to prove.
So despite the above you are faced with three practical options
1) Lie and say you are saving yourself until you know her better
2) Lie and pretend the pills are vitamins or hide them...
3) Level up and involve her in the discussion.
#1 and #2 are the easy ones and you would probably get away with either
#3 runs the risk of her cutting and running, but, if not, you will have a much deeper relationship and it won't have started out with a lie you will have to keep to yourself for the rest of your life.