I'm in the LPN program at EC Goodwin in New Britain. The differences between the schools are as large as the differences in the jobs between an LPN and an RN (ADN).
There are no specific prerequsites for LPN school, and indeed its a diploma program and not a 'traditional' college course. I believe its much harder than that of a college. There is a lot more 'clinical' or hands-on work here, and the schedule can be demanding on your family and finances.
All RN programs in the state have their own requirements, but most include courses in Anatomy and Physiology, Microbiology and some form of Mathematics. Then, it depends on which school you apply to as to when (or if) you get in... most schools have a 2 to 3 year waiting list - and that only starts AFTER you obtain all your prerequsites.
There are several bridge programs once you become an LPN that will help you to obtain an RN degree if you choose. A number of people decide nursing is not for them, some enjoy being an LPN, and some pursue their RN degree. You will learn all about articulation when you go to LPN school.
Either way you choose, stay focused and enjoy your time...
Best of luck!