I went to the US for vacation in the middle of June, then came back to my home country for two weeks. Went back to the US in the middle of July then came back home. Both times on ESTA. Now I just got an F-1 visa and want to go back there ASAP which would be when my visa comes out (around 15th of August), this time though I'd stay for a whole semester. Both my past trips had almost the same duration, 10-14 days and I was away for two weeks in between the two, and 2 weeks would be the exact same time period until my next trip.
My question is: Would customs be suspicious and possibly deny me entry to the country if both my times out of the country had the same duration? Of course I can explain to them that during June/July I was on vacation and really wanted to come go to the US after the first trip, but would that situation be too weird for them to the point where I'd be denied entry?