she sounds fine.
At this age, they do take 2 naps a day.
My son however was taking 3 naps.... until about 1 year old.
Then 2 naps from 1-2 years old.
Then now he is 3.5 years old and he takes, 1 nap a day. And that was from when he was about 3 years old.
His naps are 2 hours at the least.
He sleeps well and fine at night.
Here is a link on how much sleep a baby needs:
http://www.babycenter.com/0_how-much-sleep-does-your-chil...
Keep in mind, that 6 months old is a growth-spurt time... and intake increases. It is ALSO a time where the hit many milestones and/or change a lot developmentally and this can tweak their sleep. But in these cases, it is a phase.
Keep to a nap routine... consistency is key.
After waking, a baby usually gets tired after about 2-3 hours of being "awake." And for a baby, even a bath is an activity.
all the best,
Susan