So i have been learning about spirits through mirrors and during the ritual the mirror actually burst into peaces and all the candles in the room went out at once leaving behind nothing but the dark. Could this have been from the ritual?
Having candles too close to the mirror can heat up the glass causing it to break. Force of break could put out the candle; either by air, or piece of mirror hitting the wick. Without further circumstances, this could be explanation.
Starpower is correct. However I do not dount the fact it could be an entity, for some entities this is rather simple. It's very rare... You shouldn't worry. Next time if it happens-after you were careful accoding to Starpower's answer-I suggest considering the fact of being an entity...
It depends from a lot of things, really. Candles, room space, atmosphere in the room and so on. Next time I suggest giving it a shot outside, with the candles away from the mirror or next to it (not too close).