I received an admit (tuition fee waiver + TA) from a university for PhD in Physics. I was offered in the last month, and I replied the graduate admission director that I will inform him regarding 'accepting or declining' the offer around end of the march. (the deadline for accepting the offer on April 15)

I thought I will get maximum decisions in March but few of the universities have put me on a waiting lists and probably they will decide by April 15.

Should I email the direction to extend the days? I mean, I will ask him that II inform him by April 15.

OR, as the deadline is 15th April, it is not necessary to email him to extend the date?

I received an admit (tuition fee waiver + TA) from a university for PhD in Physics. I was offered in the last month, and I replied the graduate admission director that I will inform him regarding 'accepting or declining' the offer around end of the march. (the deadline for accepting the offer on April 15)

I thought I will get maximum decisions in March but few of the universities have put me on their waiting lists and probably they will decide by April 15.

Should I email the graduate admission director to extend the days? I mean, I will ask him that I inform him by April 15.

OR, as the deadline is 15th April, it is not necessary to email him to extend the date?