However with such an ambitious flight so soon after gaining your wings, I'm sure you'll log plenty more 'epic' journeys by the time you submit your application for CPL, so choosing which flight to nominate would pose the bigger problem!
That can be surprisingly difficult if you leave it to chance. In the 450 hours before starting my CPL I had several individual legs >300NM, and even more A-B-A return flights on the same day >300NM, but the two qualifiers were A-B-C flights I planned as A-B-A, but where I had to divert to C due to weather on return...