Getting Older Makes Me Scared

I'm 16, but I'm scared of growing up. I already have really bad abandonment issues and things like that so thinking about the passing of my loved ones scare me. I don't want it to happen, but it's inevitable. All my siblings are 7+ years older than me and my mom is turning 60 this year. I sometimes wish I didn't have older parents so I wouldn't have to worry about it. My boyfriend tries to help me, but I'm scared he'll go away too. I don't have the money to afford therapy and my mom will probably just tell me to pray if I even asked. I just want this feeling to go away, I don't want to keep staying up at night being worried. Can someone tell me how to get over this? I need help.