There's outfit selection, which might have expanded options in the future. You can currently play a female character in a punk rock leather jacket and tattered jeans or a male character in a cute skirt or skort, depending on aesthetic choice. (That's not a permanent choice; you'll be able to change your mind later in the game.)
The player character is young enough that they're going to look androgynous regardless. You can think of the prologue dream mirror showing a possible future version of the character, not a set in stone one; the game's not likely to be on a timescale long enough for it be relevant. (In other words, MC's gonna stay a cute kid the whole story.)
I do want to leave plenty of room for head canon, so most descriptions of the MC are kept relatively vague. Open to interpretation and all equally valid.