Age SHOULD NOT be a factor when it comes to whether an owner should rent/sell their property to you as long as you're a legal adult, HOWEVER, like 'Seth Captain' said, there are a bunch of other factors that they CAN deny you for. Unfortunately, many younger people do not have sufficient credit, references, or steady & reliable income... so it may feel as though you are being denied for your age.
Again, like 'Seth Captain' said, your best bet in order to score your desired property is to make a good, clean first impression and/or have someone co-sign.
If you need any help buying or renting in the Chattanooga area, id be happy to lead you in the right direction or simply answer any questions. Call or txt (423) 486.4350 or email me at aburns(AT)realtycenter(DOT)com