if you feel up to it, a dedication to the Lord and Lady, or some form of 'this is me, i wish to walk a wiccan path' introduction ritual if you don't feel 100% about dedicating to a specific deity.
you might also consider designing your own ritual to mark this occasion and repeat it every year [your own personal holiday]
in terms of 'i've done studying...now what?' you can do many things. journaling and mindfulness [i'm assuming you already mediate fairy regularly] can help you connect with your inner self and gain a deeper understanding of who you are and what you want/need. you could also focus your studies on specific things like herbs or crystals. you might also work on incorporating your magickal and mundane so your spiritual self isn't a 'circle only' type of thing. The Goddess is in the Details and Everyday Witchcraft by Deborah Blake are excellent at helping you find little ways to incorporate the magickal and mundane. To Walk a Pagan Path by Alaric Albertsson is another great read.
once you finish the studying the real work begins because you're not memorizing facts and charts but having to find that perfect balance. figure out what you want out of your path, what you wish to work with and don't. it can be confusing [and overwhelming at times i know] so just relax and take it slow.
The whole idea of a "year and a day " was never meant to be literally true. It means " at some future time ". The concept of waiting for a year and a day was so that the person had enough time to decide for certain that Wicca was the religion that they wished to dedicate themselves to for the rest of their lives.
If you have made that decision then you might want to perform some sort of simple ritual stating your intention to dedicate yourself to Wicca and to the God and the Goddess. After that, one practices by celebrating the Sabbats and Esbats, following Wiccan ethics and beliefs, and honoring your deities on a daily basis. In other words, it is time to actually put your beliefs into practice.
Remember too that there is no such thing as an end to our studies. We continue ( and we should continue ) to expand our learning throughout the rest of our lives. You don't just stop reading and studying because you've done it for a "year and a day". I have been Wiccan for over 35 years now and I am still on a journey of knowledge and exploration. The " year and a day " is not an ending, it is a beginning.
I'm really glad someone took a moment to post this! After reading through it that really cleared up a couple of things I was intending to ask my mentor about at a later point in time. So thank you! while I'm new to this Wicca is a complete clarity for me and I find myself wanting to learn more and discover what it has in store for me also its taught me alot about myself that..I didn't even know.
I started my magickal training on April, 2007. Here I am 10 years later and still learning and practicing my Craft. There is always something different to learn. So traditionally, in Wicca, you must study for a Year and a Day to learn the basics. By then you should know a lot, how to open and close a circle, meditation, grounding, how to raise energy, protection, spellcrafting, the Wheel of the Year, the Esbats and Sabbats and more. Once you have the basics, then you become yourself and can be more confident in your Art.
You can Dedicate yourself to a certain Goddess, but usually a dedication ceremony is used in a Coven setting.
Instead you could have a commitment ceremony, where you promise to honor the Goddess and to keep learning and practicing.
Good Luck on you Path.