The first eggs are peewees, so cute and small. As the pullet continues to lay they get larger. One should be able to lay only as early as 25 hours after an egg …according to the experts.. but I am positive my first layer laid one at 23-24 hours ----had it on surveillance camera in the coop. But all since are at least an hour later each day.
Since Leghorns are considered primarily layers..bet they/she will lay an egg almost every day. Expect about an hour later each day, til not enough daylight, will skip a day and start over.
Big gals, like Buff Orpingtons started laying with extra large day 1 --- but 2 of 3 in my small flock stay broody 50% of the time and don't lay at all then.
Most resources - textbooks, online comments will tell you they lay by noon…..I know that is not true. Check your nests/coop for eggs by noon and in the evening before dark and you'll see for yourself. We usually wait til late afternoon after all have laid to collect eggs now. But once, one of my bars - the runt - actually laid her egg while others were going to bed on roosts..after dark. Would never have believed it if I had not been there to witness it - on camera!
My first layer, a barred rock, laid every day for almost a week when she started laying, could not believe it. And at 19 months she still does!