Hi! I know it seems that way since I also got Ao on my first rare and my friend got Orochimaru. However, I have actually asked about it and each one has the same rate that is up to chance. Many players have received Sage Naruto as their first rare and I am happy for them and sad for myself since I already had Ao XD

I would recommend to pull in the treasures that currently help the most though like GNW Treasure. The reason is, seal scrolls takes time to ac*ulate and during the time you are saving, you can pull some free pulls in Sage Treasure and hopefully get the rare you want, without using your precious seals =p

Hope that helps!

~Jib