how many sets of leaves before maturing?

does anyone have any info on how many sets of leaves a plant will get before maturing? my plants are starting to hit the 12 inch mark but only have 8 sets of leaves, im worried about them getting to tall when i put them on 12/12 light. all of the shoots are comming in nicely between 2 sets to 4 sets of leaves on them.

they will also be a month old in 2 days.

there is no set answer to your question. the plants are generally considered mature when the leaves stop being in a set of two and instead alternate with one leaf per node. eight nodes in 12 inches is a sign of a good grow to date. as for height, you could end up with anything from 2 to 4 feet tall, depending on strain and how long you plan to continue vegging.

its asorted bag seed. im waiting for good beans i didnt think it would take this long. the plants are varying in size and height. from the looks of the overall plant and leaf blade sizes there is probably 3 diferent strains going. would i be safe to go into flowering now? i can get some pics up tonight.

you can go to 12/12 lighting any time you want, even from the beginning of your grow. the longer you veg the bigger the plant and the greater the yield, within reason.