Q.how long does it take a lime to mature?
How long does it take a lime to mature? I have to have it for a school project.

Not clear on what information you're looking for. "Mature," in terms of lime trees, means when the tree starts reliably bearing fruit. This depends somewhat on the variety of tree, and the climate, but generally between 5 and 10 years. However, that doesn't seem something you'd be doing as a school project. Are you by any chance trying to find out about growing something from a seed? It will take from one to several weeks for a seed to germinate, (that means the seed sprouts leaves and roots,) and after that you can let the baby lime tree grow as long as you want - you'll have a little plant within a couple of months. Be sure to put a number of seeds to germinate and grow - not all seeds sprout, and not all sprouts grow into plants. This article has more information: https://www.gardeningknowhow.com/edible/fruits/lime/growing-lime-trees-from-seed.htm