is going to or will, a Grammar question for future actions?

Question

My mother is going to be 50. Can I say my mother will be 50? Sometimes there is not much difference between will and going to for predicting the future. So, is this the case?

Answer 1

I am no grammer expert at all but when I read it I feel that when you use will you should put the time it will take place, my mom will be 50 in may.

Like I said I'm no expert but thats what I thought when I first read it.

Answer 2

"Going to" implies that something is gong to take place in the immediate future (like a year or less). "Will" implies a longer time before the event will take place.