Just make sure it comes from the heart! Also, if you want to let her pick out the ring, you could surprise her with another token of your affection - name a star after her, saying "I thank my lucky stars I've found you". Or, have a custom jigsaw puzzle made that says "Will you marry me?", have it put together except for one piece. Then, hand it to her and tell her she's the missing piece that you've been looking for.