Aww boho that's actually kinda cute!
Tabletop gaming in this instance mostly means dice based games. Like Dungeons and Dragons, where you have a character sheet with all of their stats and you role play your character with a bunch of other player characters and a dungeon master...the person who controls/describes the environments and non player interactions (like the bad guys,townspeople, shopkeepers, etc etc). Most outcomes of interactions (fights, persuasions, theft, etc etc) are determined by a roll of the dice!
I actually just bought a d20 (twenty sided die) necklace on etsy and i haven't taken it off in 3 days...its my geek badge of honor haha.
As for a convention...I would love to go, but I've never been to one sadly. :(