Look. Advice about life. Yes, you are still kids. Yes, sibling/family rivalries are common. Generally, older teens prefer hanging out with family their age or friends over family. It's not you. As a teen ages, it is a natural response to gravitate away from their famiies. It is a natural response, for the teen to want isolation, to live on their own. With younger cousins and siblings, it is just chalked up to immaturity. 90% of children will grow out of it. And a 15 year old cousin treating a 13 year of cousin much younger is quite common. 15 is the age most teens start becoming considered adults. A 15 year old can start working, driving, taking on more responsibility etc. It is no fault of their own, their brains just process you as younger and far more immature than them. So do not get upset with your cousins, you aren't them, you don't know what's going through their brains. The only thing you can do is have patience. With both older and younger family. You just need to remember you aren't as old, therefore you aren't seen as the person to hang out with when there are several others their age.
