Hello
I am 19 years , nearly 20 in Jan, Female
Height is 5 ft 5 inches
Weight is 102 pounds

I think I should have 110 pounds for normal??

Just my thoughts
But I don't know how to gain weight..
Can you all please help??
;);)

Thanks for the time for reading

You can't tell from those measurements. You need to look at things like the size of your thighs and hips etc.

To gain weight, eat more and do strength exercises.