Hi Alicia - congratulations on wanting to become a nurse .... we need you in the ranks. As far as getting into school, you should make application to your nursing program at your earliest opportunity. When you get close to finishing your pre-reqs, make application to the program. I had 2 classes left to finish and made application. Glad I did because they held my application active until they reviewed my grades from the last 2 classes I took. Talk with the nursing advisor at the college you will be attending and ask them when you should apply. Most often, they will be able to give you a reasonable timeframe.
If you do not get in the first round, you will have a chance after the semester begins. They ususally have a pretty high drop rate during the first 2-3 weeks of class. The program will most likely hold the final registration period open for new students who get accepted after the drops take place.
You asked about several questions about other ancillary positions in nursing and about being an LPN. An LPN is a vocational nurse that assists the RN on the nursing unit. Most often the LPN, under their practice act, can perform certain activities that an unlicensed person can not. This activity would include passing medications, doing treatments, performing basic care as well as a host of other tasks as determined by their State and facility. The LPN takes generally about 12 months to complete. In some areas it takes less, other areas it takes longer. But, it is a fair bet that becoing an LPN takes about 12 months. In addition, once you graduate from LPN school, you will be eligible to sit for the NCLEX-PN exam - which is the licensing exam to come licensed as a practice nurse (LPN).
I would recommend that you visit the American Nurses Association web page to learn a little more about nursing and the role of each discipline within the profession of nursing. Another good source of information about nursing is www.discovernursing.com
This is the Johnson & Johnson site and it will answer many of your questions. In addition, you can learn a lot about educational standards as well as options that are available to you as a Registered Nurse.
Good luck with your educational endeavors and I wish you success getting into the nursing school of your choice. Patrick