Nope - I wouldn't be letting a 13 year old look after that many kids at once... and certainly not my 8 month old! Older children are able to come and tell you if something is wrong but an 8 month old isn't. And I certainly wouldn't be letting a 13 year old I didn't know well do it! Geez, I'm funny about letting ADULTS baby sit my DD and she is nearly 2!