So the best way to go about this is getting friends your age. I started with the hardest one, sorry. I know you're a little loner, it's ok bro :)

What's that? I missed step 2?

Play at the right time. By my understanding, these sweaty 8 year old are usually offline at 7pm because they are 8. I go to bed at 7:30pm so I get that blissful half hour! Another time-wise choice would be 4-6am, because little boys need nap time. Also, around 12 noon will be a bit of peace, they will have to run into mummy's arms and be breast-fed for a good chunk of the day. If you are lucky, you will also get a 20 odd minute break at 3pm because that's usually when they get their diaper changed.

What? We haven't had step 3? Well this can be step 3's step 4's version of step 3, ok? Right good. Step 4/3 is a bit of a bonus, because it isn't how to match with other age-groups, but it is how to know if you are currently matching with the younger age group. A telltale sign would usually be them having xX__Xx in their name, or being a YT__. This is usually because at such a young age, you are unaware of how wet you are being. A second sign would be the way they chat and play. Normally an 8 year old will say things like "I am 8 and I suck at this game" Or something along these lines, they may also run in circle with a sweaty pay-to-win gun, or camp in the corner of the map and kiss my boots.