How exciting! I love solo WDW travel. I also took my 1 year old by myself which basically was a solo trip because he can't converse with me yet, and I chose to eat at whatever table service I wanted (reserving for two for the high chair, of course).
Lounges are great for solo dining and offer bar or table set ups. My favorites are Nomad Lounge at Animal Kingdom and Enchanted Rose at Grand Floridian. The former's food is supplied by the kitchen at Tiffins, while the latter offers small bites (I'm not sure if you can order from Citricos to eat at Enchanted Rose). Other first come first served lounges are attached to Narcoossee's and Citricos at Grand Floridian, Trader Sam's at Polynesian, and California Grill Lounge at Contemporary. Other resorts have bars/lounges that you should also look into, such as those at Coronado Springs and Riviera Resort. There is also the Tune-in Lounge at Hollywood Studios and the tequila spot in Mexico at Epcot, though I believe those are standing room-only bar options unless you are seated at the tequila spot (forgive me, I forget the name). Oga's is always chaotic and (I think) fun for a solo traveler, but they don't have much food. I particularly enjoy Skipper Canteen in Magic Kingdom as a solo diner because there's a lot of stuff to look at on the walls, but this is table service and I would recommend a reservation. I avoid anything where the food is served family style simply because this usually ends up being too much food for me, even if I do love the meal and characters at Garden Grill.
There are sooooo many solo travelers of all ages and demographics at the parks that you won't be out of place. Eat where you want and enjoy yourself. Pro tip, if you have trouble finding a reservation for one, search for two! This won't work at places like Cinderella's Royal Table where you pay in advance, however.
One final note on lounges is that sometimes they have weirder hours than you expect, so keep an eye on those.