August would not be too early for a number but would be for some, including those that don't start taking applications until September or, in some cases, even later. Check the colleges to which you intend to apply. Also, remember that the common application proper with required essays is only part of what is needed; many colleges that take the common app have their own supplements which you must also submit, and then the application is not complete until there is a transcript, test scores from the testing agencies, and for many colleges, recommendations. Until all required materials are in, no one who actually makes admission decisions at a college will review your file.
Getting things done earlier is better than doing it at last minute when mistakes can easily be made. Also, regardless of when you intend to apply, you should line up early those persons you want to provide recommendations because they will need a lot of lead time.