I think 'descent' is the wrong word here! Descendancy would fit the bill if indeed that word exists! Better still is 'ancestry'!
Am I right or am I right?

Lineage or heritage would be better I agree. It's the sort of thing my students come out with, although you can understand what they mean of course. Descent is a perfectly valid word when talking or origins and so forth. But no it didn't fit that sentence.