At 5’0”, only a weight of 82 lbs and lower would put you at a dangerously low BMI of 16 kg/m^(2) and lower. So you should be fine as long as you don’t suffer from any medical conditions. I’d advise you to take it easy though and start with shorter fasts. 24 hours should be a good start. You can build your way up from there after you get a feel for it.
It’s safe to fast if you don’t have any underlying medical conditions that prevent it, if you supply electrolytes and refeed safely. You should try the FAQ! And also: just consult with your doctor to be safe. We can’t give you advice without knowing your situation.