Ican not do push-ups, not even one.

what is the best thing to do?

I'm the same but I started to bench press witch kinda of helped me

It's great your trying to to improve your health first of all, First thing I would recommend is to get healthier foods in your household, ones that hold the nutrients you need to help build muscle, next I recommend to get more active outside with your friends, play games like manhunt, hide and seek, and tag. Next try to do pushups overnight while doing these things. Hope it helped

10/10 recommend bring pads/tampons with you no matter what. im 16 & i’ve had mine since i was 12 and they’re still it regular, but id suggest using the glow app, many women use it for fertility reasons but i use mine specifically for the period tracking portion and it guesses when your next period will most likely be for the next two months. i dont believe theres any way to delay your period, so id say hope for the best but make sure to bring all of your stuff just incase. have a good cruise!