can i delete the iPhotos app now I have photos?

If you never use it and are sure you don't want it, yes.

can i delete iPhotos now i have photos? I never use iPhoto anymore

If you have older iPhoto Libraries, that you did not yet migrate to Photos, keep at least a backup copy of the iPhoto application. It will probably be difficult to get iPhoto back, if you later should notice that you need to open the libraries in iPhoto to prepare them for migrating to Photos.