How should I tell this girl I like her and is it a good idea?

ok well tomorrow in the morning I plan to talk casually with this girl I like (she knows and she asked me to dance at banquet this past weekend but I refused cuz i don't dance) as we walk to cl. She seems to be a bit mad with me becuz i didn't take the opportunity but today it seemed like she wanted 2 talk with me cuz i left a message on her phone trying to explain wat happened at the banquet. But anyways I plan to tell her that I want 2 talk with her after school as we walk home from the bus and that's when I plan to sit down with her on the sidewalk and explain to her that I like her and that I want to go out with her. Is this a good idea or is it making her wait to much? Also i've liked her for a month now and i don't know if she's actually serious about liking me or if she's bluffing