well it can take up to two weeks to show signs of sex once putting a plant into flower depending on the strain. just keep a very close eye a couple times a day especially after the dark cycle. if you have a magnifying glass i would keep it close at hand to catch the first signs as soon as they appear which im sure your excited to find out. as for leaves... yeah. your gonna get new ones. some strains can double even tripple in size after flower thats why its most important to gauge your size while in the growth stage and flower before they get as tall as you want. but it varies from strain to strain from pheno to pheno. so good luck with your garden and happy watching!