Krez Shantelle’s Answer
You can actually go straight into the Bachelor of Science in Nursing degree program as long as you get accepted in the nursing school you wish to attend to. A Bachelor of Science in Nursing degree is a higher educational credential than an Associate Degree in Nursing. There are multiple reasons why some nurses take the ADN first. But based on my observation, they mainly take up ADN first because of the cost and time: it's less expensive and less time-consuming than the BSN. Most of the people I know who has ADN eventually ends up taking the BSN course though and cost them more money and time in the long run.
There are many factors you can consider when making the choice between the two degrees. But for now, ask yourself "What is my career goal"?. The nursing position you want to pursue will impact your education options. If you are still confused and having a hard time making a decision on which route to take, talk to your family/friends/teachers or an advisor from a school you're trying to get into and discuss your nursing career goals with them.
And to answer your question, the ADN is not a prerequisite to BSN. :)
You should visit in person or online with advisor d to clarify the articulation agreements with the 4 year school