teen relationship advice?

i've been with my boyfriend for three months. and i never though it would be so hard. i have never been in a relationship, but i was ready. i met this guy and he's AMAZING. he treats me so good and my family likes him and overall it's just great. he goes to a differnet school, and i trust him. he's met my parents and they like him. the thing is, my friends hate that i'm in a relationship. they think i am not talking to them a lot because of him. when i spend every waking second with them even though they treat me like shit. they're the ones pushing me away. and everyone even my sister, is just telling me that we are not going to get married, that we're going to breakup eventually, that he is going to hurt me. and i am aware that there's a REALLY small chance that we'd ever get married. i'm only 16. it makes sense. but i don't understand why everyone is treating me like i don't know that, like i don't know there's a smal chance of us getting married. i'm just trying to be happy, trying to live. but everyone just keeps focusing on the negatives. and idk what to do. only one of my friends have met him. and she says that he is really good to me and he's really nice and funny. and everyone that has not met him says the complete opposite. idk how to handle it, i'm just really overwhelmed and any sort of help/advice could do me some good.😔