If you use binary genders you use male or female ones and people tend to use the same pronouns once they start with them. If someone uses gendered pronouns you shouldn't take that to mean that's the one the subject prefers but rather that's the gender the person who wrote it perceived.

If they truly don't care to perceive a gender then a 50 / 50 pick. When I look at it's picture I honestly couldn't tell you if I perceive more male or female so I would've done same as op and picked one randomly and then for consistency not change it, even if some unrelated party tried to confuse things by making me change it.