The philosopher Phillipa Foot used to say that to consider goodness, you need to start with plants. She could have said we need to start with books and knives.
A good object is one that fulfills it's function: a good knife cuts, a good book informs or entertains. A good plant is much the same: it can survive and reproduce. A good animal, however, needs not just the right bodily structure, but the right behaviour: it needs to know what to eat and how to attract a mate. If it's a social animal, that means more behavioural requirements.
Humans are social animals, and so can only have a good life if they have the ability to thrive in society. They are also rational animals. As Aquinas said, animals go for what they need, humans for what they think they need. This means that to be good humans we need what Aristotle called practical wisdom; we all know how the best intentions may fail or even make things worse. A good person is thus one who has the abilities to lead a flourishing life in all respects.
How do we fail?
> Lack of practical wisdom, causing us to pursue false goals or the wrong means (Aristotle)
> Lack of opportunities to develop moral sensibility (Mencius)
> By concentrating on our individuality and becoming unfeeling to others (Wang Yangming)
In other words, the capacity for virtue is like that for speech: all normal people have it, but we still need to learn to exercise it. On that basis, I'd say we are born good in the sense that goodness is a natural development.