They discovered a vsd in my 13yo daughter, is it normal to be found this late?

No: A vsd is associated with a heart murmur from the blood that flows through it. That murmur can usually be heard shortly after birth. Rarely the vsd is in a location that makes the murmur more difficult to hear, but it is very uncommon to first be noted in a teenager.

Sometimes: If the shunt fraction was low, the child may grow and thrive without severe symptoms unless challenged physically by peers. Therefore unless an echocardiogram is obtained as part of a cardiology evaluation for competitive sports or because of a murmur, a small vsd may be discovered late specially is isolated.

Not really: Should be heard during routine exams. If the vsd is big it might not be picked up by auscultation but should have lead to symptoms much earlier.