Shalom,
   I have just figured out why Nissan 17 is said to be First Fruits....because that is the day that Ya'Shua arose...on the night of  Yom Rishon, first day of the week ...Ya'Shua was still in the grave.  This was the beginning of the 2nd. day of the Omer.
   The Sabbath of Nissan 15 (the sabbath of the first day of Unleavened bread) ended at sunset of weekly Shabbat.  So Ya'Shua spent a double Sabbath in the grave.  But on the 3 rd. day He arose.  The 3rd. day from Passover, but only the 2nd. day of Unleavened Bread...The third day of of Passover, is the 2nd. day of the Omer...because you start counting on the day after the Sabbath of Unleavened Bread.

So here is the line up:
Nissan 14 was wednessday night and thursday morn.
    This is Pesach
Nissan 15 was Thursday night, Friday morning...it was a Sabbath of Unleavened Bread...as well as preparation day for the weekly Shabbat.  The next day was Shabbat..so two sabbaths in a row.
Nissan 16, weekly sabbath, was also Day 1 for the Omer count. So it had two important happenings.
    As Shabbat ended...Omer two began.  First Fruits.  This was therefore the day that became named by a pagan representation of a happening that marked the 5th. day of the previous week.  Ever since, it has been wrongly represented.  It didn't represent the fulfilling of Passover...it represented the fulfilling of First Fruits.  In the middle of the day of First Fruits...as morning was breaking Ya'Shua was resurrected.
    Ya'shua said at His Last Supper, that He would fill it full of meaning when He served it in Heaven...when He would complete that Passover Season.  He would begin a return, right where He ended.
    On Omer 3...He met up with some of His disciples.  That was sort of where we are today on our Omer count.  I thought it interesting that today is the pagan "good friday" which relates to nothing.  Not the crucifixion, nor the resurrection.  "Good friday was the Sabbath of Unleavened Bread,"  in Ya'shua's day.  The Omer would not begin until night fell.  Omer 1 that year was a really special time for it joined Two Sabbaths....In Lovingkindness.  Hesed of Hesed....the ultimate Hesed (Mercy, lovingkindness).

   Think of that today and tonight.  As Shabbat prepares to arrive tonight...we will be finishing our day 3, beginning the 4th. day of the Omer count.  Ya'shua was beginning His 1st day of the Omer --Lovingkindness in Lovingkindness, still in the grave.  In action He was releasing those in bondage within the bowels of the Earth. Those who would share His first resurrection.  I suppose they had to accept Him as Messiah, it was decision time for them.
      In 2000 years, have we advanced 2 additional days in our understanding of Torah?  To the level of the 4th. day count of the Omer, the level of Understanding the Heart...Endurance in Lovingkindness?
      The counting of the Omer...7 wks. of 7 days....plus one day=50 days till Shavuot and also that many days until the 1335 days from Intafada.  Read about it in Dan. 12:12.

Shalom,
Meriam Brown