Caught topless now feel weird?

im 15 my stepbrother and his friend are 14. we are out of school for summer and my parents work. my stepbrother was at his friends house so i was home alone. yesterday i got a terrible sunburn and today i am very sore. i put some spray medicine on and it was kinda greasy and it just felt better to be topless. since i was home alone i didnt think nothing about it so i went topless i sat in living room watching tv, as my tv in my room doesnt have a satellite reciever box. i figured in living room i could hear someone if they pull up. well i accidently fell asleep. i woke up hearing some noise in kitchen i quickly jump up and put something around my top, i look and its my step brother and his friend and go to my room and put shirt on. my stepbrother friend mom dropped them off. i come out of my room and ask how long they been there they say about 15 minutes. i feel so embarassed why would they not wake me up as soon as they seen? how do i get over this akward moment they seen me topless for like 15 minutes?