I'm new to sunless tanning?

so i have a sweet 16 im going to on friday and a super busy week coming up also. i basically can only go to a tanning place on wednesday or friday. my friend (who has only done spray tanning) said if i were to spray tan on friday it wouldnt work out cuz id have to shower later and i wouldnt have enough time to get ready for the sweet 16. also im a swimmer and if i went on wednesday i have practice that night and dont know how that would turn out. but im not opposed to using the bed only because im only planning on using it once, but i was wondering if takes more than one visit to the tanning salon to actually get results from the bed?? thank you