Hello Maly, if you order customized size now (about 2-3 weeks making costume time) and use the fastest shipping method (Premium Express, 3-6 days shipping time), it will reach you before Aug 20th. But use the fastest shipping will cost extra payment.
*All shipping information (including methods, cost & estimated delivered date) will be shown in order page, before payment; you can pay extra cost to upgrade shipping method there.
*Please remember to mark down the date (you need it) in the order form when you order it. :)