Simply calculating, last day in August, If you are inside Thailand on the initial 90 days of the visa you have entered Thailand in May and at that time the borders where already closed, so not possible.
As you are on an Extension of Stay based on study in Thailand you can EDIT
Mr
@Tod ********
just told me that you can switch into an Extension of Stay based on being over 50 years of age at your local Immigration Office as long as you can meet the requirements.