hge gave me a birthday present that was overly expensive...too early in our relationship?

okay, so my boyfriend of 2 months gave me a golden necklace with a gold heart on it. i dunno, i mean is this normal? it must've costed at least $120 or something, i have no idea. i am ow 15, he's 16. help please. what should i say? when he gave it to me i just looked really surprized and happy that i got such a thoughtful gift. but when he left, i opened it before i went to bed, and i immediatly realized he spent WAY too much on it. i really love this necklace, but i cant stop thinking that he spent too much...
sorry, i turned 16! it might've been such a special gift because sweet sixteen.. dunno

talk to him, tell him your concerns, if he can talk you into keeping it, keep it, if not give it back, but either way thank him for his thoughtfulness.