Hmmmm how strange! Does it actually say the reviews have been deleted or you just can't see them?
I'm not sure why you would not be able to see them but if the reviews have been deleted, it would suggest there have been some issues with previous host and the guest has contacted Airbnb who have reviewed full details including the actual reviews and decided the reviews warrant being removed; you could view this in a positive or negative way.
Personally, right now my concern would be that your listing is for 5 people but you will be letting to 6 people stay in the property as such if there are any issues down the line, you won't be covered by Airbnb. It’s a risk you have to decide if is worth taking.
Ama