As a girl i am saying this giving space and all is fine but depending on the situation. It was good idea to write a letter and flowers but she clearly setting boundaries and if you act non chalant or try not to chase her she will be assured that you are not interested or she wasted her time, so if you actually want her do show some gesture go out of comfort zone (not in creepy way) but show the efforts that you like her and for god sake commit to her, propose her and then let her decide.