after its first servie the oil on the dipstick is black is that ok

There's some old oil in the passages that doesn't drain out during an oil change, perhaps as much as two quarts. Some new oil is already black. That often applies to oil formulated specifically for diesel engines.

To check your new oil, wad up some toilet paper, then place a drop of oil on it from the dipstick. Let it sit overnight and look at it the next day. Any carbon or dirt in the oil will stay in the middle of the spot but the oil will migrate into a really big spot. You can expect to find a little dirt in the middle but the size of that dirt spot will give you an idea of the amount. That amount should be greatest right before an oil change and be very small right after.