I am by no means an expert here, but I would say you should prepare for it as you would prepare for NO Mass- reflection, quiet time, etc.
I would perhaps try to find some sort of guide/pamphlet on what is going on, because the first time can be very overwhelming. I recommend the Treasure and Tradition book.
Finally, regarding the mantilla for women, it is preferable but not required. I would say about 1/2 of women attending the Tridentine Mass don’t wear one. However, it is much more preferable.
Just a small tip regarding the mantilla, unmarried women should wear any color except black, while married women should wear black. One of my friends in high school accidentally wore a black veil once- we still tease her about it!