I am 43 and want to return to school for nursing, am I too old for this profession?

I have worked in the financial services industry for 20 years. I feel nursing is my calling. I have a 28 , a 23 , a 9 and a 6 year old. I can finally return to school, but is nursing school too difficult with a full time family and a fulltime job? I am thinking about taking a 19 month night course to become a LVN. While working days 7am-4pm.