What would be some advantages and disadvantages of being a nurse?

You already mentioned helping others. It is a very rewarding to have someone appreciate what you have done for them. Nursing is like anything else; there are pros and cons, ups and downs. There can be disadvantages, but they may not be all negative. It just depends on how one views them. 

1. Shift work can be seen as a disadvantage if working 12hr shifts because it takes up most of the day and can be tiring. However, this can be an advantage as well because longer shifts usually mean more time off (ie- three 12hr shifts on and 4 days off). 
2. Physical Demands. Nurses are often on their feet and moving a lot in their shifts. Some fields also require some lifting. A positive outlook is a sedentary lifestyle is not healthy, so this keeps us moving. I’ve found that good shoes and compression socks/stockings help with aching legs/feet.
3. Holidays. Depending on the field and setting of work nurses may have to work holidays. Obviously a nurse doesn’t want to miss a holiday with her family, but neither does the patient who is stuck in the hospital. Patients and families seem to be very appreciative of the care they receive on holidays because they realize the nurse’s sacrifice. And holiday schedules rotate, so you won’t get stuck working all of them.
4. It can be an emotional job. Sometimes a patient does not want nor appreciate the help at that time and this can be frustrating. Nurse see all phases of life; from start to end. The emotions can be joyous or sad; lending support to a family who has lost a loved one or celebrating a birth with new parents. 

So, some of those disadvantages can be spun into advantages. Nursing is also very flexible. If one path is not a good fit, there are so many others to try.

Great question!