Upvote:0
First, don't be nervous. If it's already booked, there's no point in worrying.
So, it's a ~45 ride from DCA to IAD in 'average' conditions. So, 4hrs 45min is plenty of time.
However, given the date, this itinerary is 'weather permitting' on both ends.
I would take Uber. $30 maybe, give or take.