You can try this site below birth families can also register here. I took a quick look for you using the date of birth you provided but didn't find any Marjorie Young looking for her family there is another Young there in March but she was born in London, Ontario so that's not her. But it might be worth a try and add your name just in case she starts looking for her birth family. I've seen many people have a lot of success after posting on the site below. Another great site is Cousin Connect a lot of people looking for birth families also post there. After posting on Cousin Connect I was able to fill in a lot of missing information on my search for info on my g-grandfather.
Another possible source to try is the Toronto Papers since sometimes the adopted person puts in an ad in the paper seeking information on their birth family. Now this is a long shot but might be worth a try, looking for adoption notices around that time. Sometimes the adopted parents put in a notice in the paper around that time now of course there may have been many other adoptions around that time but it won't hurt to check.
If your in Toronto you can have free access to the Toronto Star and Globe and Mail using your library card by logging into the library web site. http://www.canadianadopteesregistry.org/http://www.cousinconnect.com/