Hi there! I'm at work and only lurk occasionally, but can recommend a few agencies and an attorney (2 are in PA and one in Florida). I have 2 DDs (3 and 20 months) through open adoption; they are biological siblings, both adopted at birth. My DH was 46 when we adopted our 1st and I was 39. Age can be an issue depending on agency, lawyer, and I think, some states. We were listed with Adoptions From the Heart (Wynnwood, PA.)- our original agency, but ultimately ended up using Steven Dubin, Esquire (Southampton, PA.) along with Heart of Adoptions (Tampa, Fl) who represented the birthparents (they were in Florida). We liked all 3, and would recommend all of them. However, using an attorney is vastly different from an agency, although all were similar cost wise (about $38K + travel). I would be happy to share my experience and give you more background on both if you provide your email (mine has our name in it, so I don't want to post it). We had a great experience (but, it was marginally long, and lots of paperwork). I can tell you, I couldn't love these little girls any more if I gave birth to them (and sometimes I forget that I didn't).
Good luck exploring your options, let me know if you would like any more information. Also, you can google my log-in and I'm sure track many posts on this board and the Green "Still TTC" board about my experience and process.