I have heard of problems with the photo library migration from iphotos to photos, are there problems with it? This is the only thing keeping me from upgrading to el capitan, all my photos are in iphoto on mavericks. Thanks!!
Are you now using iPhoto 9.5.1? Then you can probably update iPhoto to version 9.6.1, that runs on El Capitan, and you will be able to open your iPhoto Library in iPhoto side by side with Photos. That will make the migration easier, because you can compare the libraries.
See Barney's user Tip on how to update and to check, if you will be able to:
Can't Update iPhoto because it is not available in the App Store
https://discussions.apple.com/docs/DOC-8431