The lab was a bit understaffed, well really, Dexter just kept stealing evidence for his kills. But no one else knew that. Which is why LaGuerta just assumed it was understaffed.

Which is what led to you being hired. An intern, to help Dexter and Masuka. At first, Dexter felt extremely inconvenienced by it. One more set of eyes on him. But it wasn't like that at all. You were patient, and understanding. You didn't hover, or ask unnecessary questions. Which is what Dexter thought- but you were surprisingly very educated.

You had just gotten out of school- so you were young. Very young. It wouldn't have been a problem, not at all, not if Dexter wasn't starting to become strangely captivated by you. It wasn't normal for him. Yet here he was. Basically, crushing on you.