That's a beautiful necklace with a beautiful clasp! Congrats on your score!
And sorry to hear of tricky family matters. I hope things get better soon. In the meantime, celebrate your sister's graduation and enjoy your new jewelry.
Everything is beautiful, earrings, necklace and dress, but I think for the wedding I personally would go with just dress and earrings; the dress is very intricate and with your hair and make up done, it will all look complete.
Wonderful, mesmerizing colours and combination of metal and stones, but also the proportions are perfect, it sits very well on you. Enjoy in good health!