I don't know about the law where you are but in the UK a closed adoption is exactly that so there is no contact whatsoever. However an adoptee can search once they turn 18 with or without the help of an intermediary ... law different in Canada and USA. The law has changed here recently that birth families can search using a registered intermediary (it's illegal to use an unregistered intermediary) although there's nothing stopping them search without outside help.
You have been given good advice though. My son's adoption was closed nor did I know about open adoptions so I don't know how I would feel in your position.
Pip
