...terminamos nuestro trabajo de grado en abril, a finales de abril
[Captions 15-6, Patricia Marti > Estudios Médicos > 1]
With all Patricia's talk of school requirements, you could be forgiven for initially thinking 'a finales de abril' referred to her final exams. But the phrase actually means "at the end of April" or "around the end of April." And so, the quote cited above is translated as: "....we'll finish our thesis in April, at the end of April."
f Patricia's project were to be delayed, she might say:
...terminamos nuestro trabajo de grado a principios de mayo
...terminamos nuestro trabajo de grado a mediados de mayo
As you probably guessed, those two phrases above mean "around the beginning of May" and "around the middle of May" respectively.
If she wanted to be even more vague, Patricia could also use the common phrase a mediados de año which means "around the middle of year." As an adjective, mediado(a) means "half-full" or "half-empty," depending on how you look at it.