My boy is tiny too... I know you have a female so can't truly compare, but at 16 months old my boy is just 46 lbs. He is not malnourished, although the vet usually says he could stand to gain a couple of pounds, she is never concerned for his health. I know they fill out until they are 18 to 24 months old, but I have serious doubts that my boy will ever get to the breed standard size for males LOL You girl could just be small... it does happen, although here in the USA most boxers are much larger than the standard, rather than smaller... but it
can happen the other way around
