I see some sagittarius in there, but i cant really say if it is a sagittarius..:
"a good physique" (this come from rising sign lol)
"I have a ton of interests....sports, travel, ... languages"
"I couldn't lie if I tried!" (this one isnt only sagittarius, but it steps out mostly in them)
"I love the beach"
"when he instigates things having to do with that I tell it like it is" (straight forward you mean :P)
"sleep deprived." (so active you cant sleep lol, mars influence, and yes, i have a sadgie mars, so i can say, i have that problem)
I also see some capricorn influence:
"People who don't know me think I'm quiet" (i also have that problem, but in the end i am quiet)
"I guess I can be introverted sometimes but that's more becuase I'm depressed probably." (in my case i just dont click with anyone, people are so "about themselves" screws me a bit)
"I'm really shy around guys and screw things up when I like one" (^^) (i also have that problem, i always had "trust and telling how i feel" issues must be my venus in capricorns fault)
"I couldn't lie if I tried!" (more sadgie nevertheless)
"I am chronically stressed"
About the being borned "close to"... it could be more of planets being placed in the previous sign, and not more of a "cuspian" aspect, as that pretty much doesnt exist... im an aquarius at 0.10 degrees and i have no assemblances to capricorns... more on the contrary, im not ambitious... i do dream of living big, but thats my neptune in capricorn... also my quietness is my mercury in capricorn... i also have my venus, saturn and uranus in capricorn as well, whilst i believe and respect 3 rights... liberty, equality, and fratnership, and that is aquarian, and not capricorn, i do not believe in working to achieve your carriers, i know i have to work, but my mind isnt about work, carrier or money 24/7... i hardly care about it