I noticed the same dark and dirty look when i changed my oil at 10k (after the initial 3750 done by dealership). I assume this is not unusual but the new oil is a bright yellow and old oil is dark reddish brown? Is this a synthetic thing? Considering this si the first car i do my own oil changes Im not sure.
Also Im probably going to change the oil every 10k miles from now on because i drive it really easy and ill prob still be changing it a couple times a year with that interval.
I used penzoil the first change and bought mobile 1 (advanced fuel economy or something) for the next oil change in about 2k miles.