Is this asking out plan good?

So there is this girl and I am pretty sure she likes me... I already asked her out to prom which is near the end of May and she said yes, and every time we see each other she gives me a big hug (trust me she does not give very many guys big hugs for anything) so I would like to ask her out on a date now. My friend who apparently has "little birdies" he talks to told me I should wait until next weekend because she takes the AP History test on Friday which I know she is studying very hard for. She will have a softball game on Saturday but she should be back home by the middle of the afternoon. And I am volunteering at something at school from 2 until 6. So I will maybe on Wednesday or Thursday (is this a good day of the week?) say something like "You doing anything this weekend?" And I say "well I am volunteering at this thing until 6... want to maybe hang out after that?" And we hang out until maybe like 9. By the way the sun sets at like 8:50 it should be nice.