Creepy. is this just me or wtf?

So... i was babysitting my cousin cause my aunt was out with my mom so the house was empty. my cousin is less than a year old and she was sleeping. my aunt lives in the second floor of the house i was in the first floor because the baby was sleeping in bed. and i had the radio thing to hear if she wakes up also i was going to see her every15 mins. so i go and she's not there and i was like wtf i looked everywhere i almost cried! i was so scared so i opened all doors of the house and finally i found her in the CLOSED closet 3 rooms away tht were all CLOSED and she was still sleeping. i got her and took her to the first floor's livingroom. i didn't tell anyone cause i knw they'll be upset. i'm 17 and well losing a child... big no no. also how the hell the baby got there??? it's impossible!!! i'm very incredulous... but seriously... wtf?? can anyone give me a reasonable explanation??? i'm kinda freaked out