Not certain, really. I'm better with some geo species than others, some closely related species are pretty hard to tell apart, even more so as juvies. I'd suggest female Tapajos red/orange head, but the tail should be more striped/striated than the spots on yours. But maybe the spots will fuse into stripes in time. Tail pattern (and blotch) can vary a little on geo tapajos, but they definitely end up more striped/striated ime.
Where did you get it? Tapajos have become reasonably common, something you might see at a lfs, while something like megasema would be more rare. I think megasema generally have a larger blotch, don't they, also striped tails, but I can't rule it out, they'd look similar at that size and then there's the dorsal fin. Images do suggest a faint hint of orange on the face on my screen. If it's female, females have less orange, of course. But from about that size it you should see the red/orange develop gradually (along with the tail stripes) if it's a geo tapajos.