VWP and Esta Question???? Will I be OK???

Hi there,

I am writing about questions for US entry procedure when I arrived at LAX airport.

Firstly, I am Australian (holding Aussie passport). I paid $14 for esta pre-clearance to its ONLY official website: https://esta.cbp.dhs.gov/esta/.

Then I have my returning ticket for 39 Days (27th June to 5th August, Still under 90 days). I have sufficient funds (I will bring around $2500 - $3000) for my whole stay. Finally I have an US Address (my Hostel for my first night in LA).

Before Contiki main tour, I will attend a Topdeck tour (Prelude) where will be finished in San Francisco on 6th July. Then, I have booked a contiki tour (Main) for Southern Adventure. (departing on 8th July)...After the tour, I intended to spend some time in Chicago and Philadelphia to visit my US friends. I know the immigration officers will ask me some standard questions about my intention of staying in the US.

"Why are you coming to the US?" and "How long will you be staying for?" .....do you know Any additional questions may be asked to me by the officer ? Can anyone please comment that will I be fine during Customs clearance?

Please This is my first time to travel to the US as an adult! This is also my first time to do Both Contiki and Topdeck Tours together! Plus visiting my US friends! What a combo!

Feel excited but a bit nervous ..
Thank you!