Maybe it is an Aspie thing, maybe it isn't, but I find that when I write in third person I get too invested in world building and exposition, while first person anchors me to a character, and the limitations of their ability to observe. In first drafts, I'll often misrepresent a character's morality or character in several instances in third person, but have a better sense of it through their eyes.
That being said, most educators and professional writers will argue against novices writing in first person. If you're going to do it, you'd better have a damn good reason for it. An unreliable narrator, a twist, or something. Most stories just don't need to be first person, and read better otherwise.