adoption

i need some help😞 I'm currently 14 & 29 weeks 1 day pregnant with my baby boy. i'll be 15 when he's born. the father (my boyfriend) is 15 and will be 16 in September, 4 months after our boys born. my parents are pushing adoption on me, saying its all their choice and i have no say and neither does my boyfriends family. legally they're the ones who don't have a say. i have an appointment with my mom and an adoption agencies to talk to a counselor about how adoption works, legal process, ect to get us on the same page. the lady at school who works with teen moms or expecting teens suggested we do this (knowing our situation about me wanting to parent and my mom wanting adoption). me and my boyfriend both have jobs and have saved all our paychecks since we found out. we have so much support from his family and all my friends and my older sister (21). we know we will be able to provide for him all his needs and a lot of wants. we understand hes our baby and don't expect anyone else to care/raise him. his family does not want to do adoption. the appointment is Thursday morning and i would just like some advice to tell the counselor and my mom so my mom can understand in the end its me and my boyfriend who sign the adoption papers and legally she has no say. im just so sad and constantly cry about the thought of giving my boy away. sorry this is so long.. 
*** UPDATE ***
my mom and dad are now supportive and are letting me stay at home with my son. they understand i'm keeping him and are done pushing adoption on me. Thanks for all your help!