Hey whats up from Miami , FL

I am new to the world of salamanders & i bought a tiger salamander larvae about 5 months ago , i got it at 5 inches ,it is at 7 now , it is well fed , has a lot of hiding spots in its tank , also i know its bad to put gravel as a substrate but i pretty much hand feed it always & its food never touches the gravel so it doesnt suck it up not really agressive at all, when i walk in the room it sometimes follows me in its tank lol , pretty cute critter but now the problem is that i keep referring to it as an "it" because im not sure whether its a male or female , it has a small little hump under behind the back legs but not a big one like ive seen online , also i would like to know what species do i have because when i bought it , it was called just "water dog" but i want to be sure , thank you in advance

ps. i attached a couple of pics to see if anyone can help

Hand-feeding doesn't prevent grazing. Ambystomatids are 'rooters' and will dig around through the gravel for anything that looks like food (including poop, gross). So any amount of gravel is dangerous.