it really depends on the person. I would ask a doctor if I were you :)
Im 32+5 and work 2 jobs and it is getting very difficult especially on my feet. One is childcare and another is retail and most of the time im working a straight 14 hr day. It can be really stressful with all the pain and you are so exhausted. I cant afford to quit one no matter how muh i want to. The farther you are the harder it will get. Your feet/knees/back will hurt like none other and your ankles will start to swell alot from standing so much. When you get to that point jus drink alot of water and try to sit whenever you can.
Usually if you were doing it before it's OK to keep doing but as you get further along might b hard to b on your feet all day. Your body will definitely tell u when enough is enough just listen to your body and rest when you can
because my dad wants me to quit one if the jobs but right now that's not really an option. but if its not good for me I will.
I don't think it's bad for right now but eventually it may get harder. Just let your manager know eventually and make sure you can get a break every few hours to sit down and hydrate, all the standing could take it's toll. But your body will be it's own indicator if it's too much, you will know when it's time to take it easier.