Several places you ask for a pedal change of a semitone which would be too quick to execute: I can see these in measure 18, 25, 80, 85, and elsewhere. A few can be remedied just be using enharmonic equivalents but some will need re-writing to work. In general, you should give the player about 1-2 seconds to change the pedal, unless you want a pedal glissando as a special effect. Also be careful of writing repeated notes that are loud and follow quickly, as the player will find it difficult to re-play the note when the string is still vibrating.
Otherwise, harp writing is generally very good and not too difficult. Everything seems to be appropriate for the tempo it is written at. Some things like the use of enharmonic equivalents around 44-45 is a very good way of getting round a problem and creating a certain effect. If you do need pedal changes be sure to mark them in the score to aid the player.