Dates are hybrids and are not true to seed implying that when you plant the date from the seed, its unlikely that you will get dates that taste just like the one from which you got the seed.
Obtaining planting material
If you have a date that you would want to plant when you know where the mother plant is, find the mother plant and get a sucker from the mother plant and use it for planting.
When you plant dates from seed, some of them will be male while others will be female and this takes about 5 years for one to distinguish whether the date is male or female.
When you plant dates from seed, dates produced by about 90% of the female dates will be inedible because they wont have a good taste.