Well, if you did it as exactly how it's written on joyofsatan then it was accepted.
Some people say they experience a lot of joy after they've done the dedication ritual. For me, i didn't experience joy. i felt a weird emotion i still can't figure out what was it, to be honest the emotion i felt wasn't good, nor bad. It was just weird, although ever since i dedicated my soul, my life has meaning and i feel loved.
As far as you're a Gentile, your dedication was accepted. Now prove Satan that you really mean it and start meditating! read joyofsatan.org! read all of it and keep on improving yourself! Show your love to Satan and he won't disappoint you in showing his love back to you!
HAIL SATAN FOR EVER!!!!