First, congrats to you and your daughter!  That’s quite an accomplishment.

I’m assuming you will already be focused on demonstrating humility, gratitude and gentlemanliness.  I would encourage you to channel these same qualities through attire.  The basic classics never fail, such as a white or blue or pink oxford cloth button down shirt and tan chinos.  You may bring a navy blazer too, but if you determine that’s too formal or warm, it can quickly be removed.  Finally, for your footwear  — and this is often overlooked – I recommended getting your leather shoes shined. 

cheers