There is actually 2 things I would do differently.
The first thing is I would allow myself to grieve more and not just try to move on with my life. By the time my daughter was a year old I no longer talked about her. I tried to cover up that I ever had her. I assumed this was how you are supposed to deal with adoption. 17 years ago there was no example of how to be a birthmom. Adoption has changed so much in this short time.
The second would be to write to my daughter and her adoptive parents more when she was younger. I always assumed that writing my daughter was for my benefit and not for her. I really didn’t think she would need more for anything. I now found out that she really needed to know about me and she needed to know that she was wanted and loved. I gave her up because I loved her and wanted her to have more than I could have at the time. I wish I could have gotten to know her better when she was little.