Interjection
Not true at all. Boys have more mitzvos and obligations. We have a chiyuv to learn Torah and to be a good boy a boy has to excell at his mitzvos as well as his learning at the same time not give in to all the yetzer horas that pull at us. A girl has to dress and act w tznius and also not be into movies. Women do not have the yetzer hora boys have for the opposite gender. You will never understand even if I wrote you 10 pages worth. The yetzer works much harder on a boy in all areas and especially in that as well as in the area of bittul Torah. It is brought down in sefarim that girls are born on a higher level or more perfected level and therefore are closer to Hashem and more spiritual by nature also girls usually dont have an ego problem as many men do which makes it difficult to submit to another and do what someone else (meaning Hashem) tells us.
One example of the differences between boys and girls is that it is very easy for many girls to Daven with kavannah and emotion and to even cry by Davening and feel close to Hashem (unless they did a whole bunch of things which puts up a blockage.) For men such a thing takes a LOT of work to be able to get emotional and feel Davening.
Ok I may be all over the place here and not so coherent but bottom line it really is a lot harder to be a good boy. Im not saying there arent challenges for girls. Im sure there are, but since less is obligated of you the challenge must be less and the Yetzer hora doesnt have that much to bug girls about. If a girl doesnt actively look for trouble trouble wont usually find her. By a boy the yetzer hora is constantly harassing us to do or not do various things.