Graduation

In a few weeks I will be finally Graduating from university ^_^
I brought a dress in preparation a few months ago but I am wondering which is the right choice.
PLEASE HELP!

 This is the dress i brought originally with a voucher I had been given for the awesome shop Blue Banana. I had to buy a new waist belt as the one that came with the dress was a little flimsy.

The first is with a petticoat.

 This is without the petticoat? yay or nay? with or without?

 This dress I wore when I was 16, and I am going to be 22 next saturday :O I am shocked it still fits so well. I also wore this to my dad's graduation.

 Is this more suitable for mine?

 This dress has been featured on here before, my amazing fiance brought it for my birthday a few years ago. I love the back and the hints of red in the black and white.

But is it suitable for a graduation?

I am well and truly stuck!! Depending on the dress depends on the heels.

Please Help!!