Uhm... it's a little difficult to follow with all those unnecessary commas chopping up the sentence. ''My mom is 5 foot 4 on a good day, 5 foot 2 I think in real life, and she is very sweet and very nice.'' I think it implies that her mother is not always happy. On a good day, she would feel positive and stand taller... two inches taller.

I suppose she is speaking about her mother's height. It is 5 feet, 4 inches (64 inches, 1 foot being equivalent to 12 inches) on a good day (wearing high heeled-shoes, perhaps?) and 5 feet, 2 inches (62 inches) "in real life".