Now. If heifers you may see some signs now. I had one heifer this year, the youngest that didn't respond to synchronising nor again 3 weeks later. I put the bull in and thought she may have been in season a couple of weeks later but not convinced. She was always a bit long and strung out and tucked up in the flank. I went to preg test her last week about 3 months after I suspected the bull was with her expecting to find her open and to send her off. When I got her in and looked at her I almost didn't bother palpating her. Her coat had slicked off (summer here) she was filled in in the flank and just had that look of wellness about her. I did palpate her and she was 3 months pregnant. I think that is the case with most of my heifers, they become settled and have that healthy look and put on weight rapidly soon after falling pregnant.
Ken