Some pianists, (many well-known concert artists, in fact) find playing from memory easy, and some find it very difficult. The pointers in this article, from Pianist magazine, may help.

What is the secret of successful practise? Don't play the wrong notes! Does that sound simplistic? Bear with me.

It seems to me that there are two problems with ornaments: technical and visual. The technical aspect is not just that students can't get their fingers around ornaments on the piano

I constantly re-iterate "Pitch, Rhythm, Fingering" when students start to learn a new piece: it helps their learning. Pitch and Rhythm alone are not enough.