Do I need to pay my Philhealth membership immediately even though I'm a fresh grad?

I'm a fresh grad, handling government ID'S. I just got my PhilHealth membership, and they said I need to pay 500 per month contribution right away even though I'm a first time job seeker.

Is it okay that I can't pay right away? My membership is listed as voluntary. Will it accumulate if I haven't paid right away? (Still finding work)