You are on loestrin 24 can you still get pregnant in the first 5-7 days after starting a your second pack?
Providing you haven't missed any pills and you've been on the pill for over a month, you will be protected against pregnancy.
Are you wondering if you can get pregnant without having had your first period? Well, yes you can. If you're having unprotected sex when your first menstrual cycle is starting, then you can get pregnant witout having had a period first. That'd be unsuitably early to start having sex, and terribly early to become pregnant.