Dear Mariah, I love this field of nursing as well! You first need to become an RN- I would recommend that you get into a program and earn your BSN (Bachelor's of Science in Nursing). There are LOTS of schools that can provide you with this. It takes 4 years of college to get your BSN. After you get that, you will take a test to become an RN. It's called the NCLEX. This test will be offered to you after you complete your degree and your school sends information to the state you live in to take the test.
When you are an RN, you will interview for the position you want. If you get into an NICU right out of school you are very lucky. I have hired several "new grads" and taught them the skills they need to daily care for babies. If you can't get an NICU position after school, then I would suggest that you go to an ADULT ICU. This will prepare you to perform many of the same tasks- use a ventilator, start IVs, monitor vital signs, etc. After a year of experience in an ADULT ICU, then watch for job postings in the NICU of your choice. You are more likely to get a position with this experience.
Best of luck to you! I have worked in the NICU for almost 30 years and find it very rewarding.