I'm furry noob, and I recently revealed my fursona and first commissioned artwork
here. My post includes the background for her basic characteristics, so you can see that there was no single, all-powerful inspiration. She's a blend of real-life references and (obviously) fantasy. I was drawn to babyfur specifically as a fun, cute way to project my little side. People seem to come at this from all different angles, though. I think
@mistykitty's "go with what feels right" is probably as close as you can get to universal advice.
If you're still thinking about fundamental things like species, and want to see how your choices might manifest visually, I would definitely suggest joining furaffinity.net, or perhaps another furry site. Browse user profiles and the galleries of different furry artists. Even if you don't have an immediate desire to commission artwork of your fursona, visual aids can really help your thinking along. You can "favorite" artwork and then review your favorites to spot patterns in the things you like. I was fairly resolved on rabbit/bunny as a species going in, but still found it really helpful to look at what was out there.
Have fun, and we look forward to seeing/hearing about what you come up with!