The absolute best lunar calendar is... your eyes! Watch the moon at night. At 7 days it's the 'First Quarter Half-Moon' and the moon will look like a half moon with the half on the right visible and the half on the left dark (in the northern hemisphere).
Here's a great site for seeing moon phases visually:
https://www.moonconnection.com/moon_...calendar.phtml
Note that the half-moon is actually the 7th or 8th day. What you're really looking for is the exact moment where the moon is square the sun, which is March 29 at 4:30 PM EST (8:30 PM UTC). Depending on how many degrees you consider acceptable for an aspect between the sun and mood, you have ~8 hours for 4° or ~12 hours for 6° (meaning a 24 hour period beginning at 4:30 am EST / 8:30 AM UTC on March 29).
Hope this helps!