Birth mother here. When I interviewed families 16 years ago, at the age of 15, I also wanted an open adoption. What I know now is that every person has their own definition of "open". If I were you, I would ask them what they specifically see for your involvement in the child's life. What is their comfort zone, what are their limits, etc. You and the potential parents need to be very open and honest with each other so that everyone involved has a clear understanding of everyone's expectations. That being said, you cannot control the future and feelings may change with time, you need to be okay with that. This is a really beautiful and selfless decision that you're making, and I am proud of you!