Second morning urine or evening urine is actually best. Every one thinks fmu because they think its more concentrated, but its actually just because your likely to pee longer first thing so you'll have enough to do the test. The amount of hcg in your urine isn't any less later in the day, the levels dont change, but you may not have as full a bladder later in the day so you pee less which equals less hormone on the test which gives a fainter line. Go with the first test you took, and congratulations!
May I ask why you tested again after a good bfp? Just curious as I always see people testing again and again after a positive and I was curious as to why they keep testing.