Past grades

You need to ask the school to which you are planning to apply. Some schools allow the good grade to knock the bad grade off. Others just add the good grade to the total. We can't answer for your particular school.

As roser 13 said we can't know. However don't feel behind at 22, don't give up. Most nurses I know started their nursing careers in their late 20's to early 30's, and many even later than that!

Few people, whatever their career goal is, attain that goal as easy as 1,2,3. There will be roadblocks, expect them, and find alternate routes.

That would depend on the school though I don't see why they wouldn't recognize the new grade. Getting a B after getting an F shows preserverance, self reflection and resilience to adversity. You worked hard the second time and should be recognized for it

It depends on the school's admission policies. Some only look and newest score, some average scores, some don't allow repeats, and others don't care how many times you repeat. The only way to know is to contact the school directly.

Also at 22 you still have a lot of life a head of you - most of my class of nursing students are between 25 and 35 so you are on the young side yet! I think if you work at it you will get into school some where.