well like everyone says there are no real levels with magic. it all comes down to experience, some have more than others. when it comes to magic, you should start with low forms of magic, like simple candle spells, or certain teas and chants, things that require concentration, and not many items. these spells will help you learn the basics like energy work, circle casting, colour associations and so on, in order to move on to high magic.
high magic carries a greater risk than low forms of magic. high magic requires more ingredients, might ask you to cast for several nights in a row, require more energy, and possibly call on a specific deity.
personally, for your year and a day, stick with low magic, then move up to high magic. spells like curses and and summonings though i'd avoid for another year until you feel confident enough. with all magic though knowledge is the key. you need to know what your doing. it might not go exactly as how you planed the first time you cast, but with practice things will work out. someone who just picked up a copy of Wicca for Life shouldn't automatically summon a dragon, they'll get seriously hurt. read the book cover to cover, work on shielding while meditating, a chant or two, then start casting spells.
same goes for practicing without spell use [i've met Pagans who don't cast] it's knowledge and experience that determines their 'level'. while i wouldn't use the world 'level' i'd go with comfort zone, how comfortable one feels doing something, be it a spell, or a ritual, or whatever. if you have a nibbling doubt you shouldn't, then don't. make sure though this doubt isn't fear of doing something wrong.
one final point. you don't need a mentor. it's fun to have someone to help you and double check when doing things, but eventually you'll have to study on your own. if you don't know how, you're in trouble. [the old teach a man to fish vs. give a man a fish thing.]