Really wide petiole wings. Got any fruit to show us? I think once you get fruit and can taste it, you'll have a better idea.

It doesn't produce fruit yet but it's from seed and the thorns are long and the leaves have somewhat a light orangey smell.

From the leaves it looks like a grapefruit.

It does look like it

How do you know it's grown from seed? Did you start it from seed and just don't recall the fruit that it came from ?