Hi Marlena,
Hope you are well.
You would not need a middle bracket as the roller brackets support this width, you would have two brackets for each end and the tube would not bend as depending on the width and drop we would increase the tube size if necessary, please see the link below:
You may also prefer a motorised roller if this is going to be in a kids room, please see the link below:
Please let me know if you need any further help In the meantime as I am more than happy to help you.
Best Regards
Customer Service Advisor
Emma