I received a post dated check from a tenant for rent which is already very past due. Can I get in legal trou

I received a post dated check from a tenant for rent which is already very past due. There have been repeated problems every month in getting this tenant's rent. The lease ends on Oct. 31st and I financially need to receive Sept's rent and then serve her with a letter that her lease will not be renewed and that she needs to vacate the premises by Oct. 31st. Can I get in any legal trouble if I cash that check prior to the date on the check, of course provided the bank teller processes it before the date on the check? Could I be legally held responsible for any bank fees she may incur for other checks that may bounce due to my cashing the check now?