Feel left out at my small development shop...is my company's culture typical?

I've been with my current shop for about 2 years. Was at a brokerage for less than a year before that. Life has been good. I have gained a lot of exposure to all facets of the business. My hours are good, and I don't have any nightmare coworkers or anything. Despite Covid, I was surprised with an annual bonus way bigger than I imagined possible (>50% of my base salary). I am incredibly fortunate to have my current job in this job market, and I don't foresee my company having any hiccups in the next little bit, due to our specific segment.

Unfortunately, I'd say the "culture" of my company leaves a lot to be desired. This is mainly due to the big gap between the senior and the junior employees. There is only 15 of us.

Here is the type of stuff I am mentioning: * The higher ups slough off doing any kind of work around the office. They are constantly dipping out at 10 or 11 AM and don't come back. It can be real slow in some parts of the year. At the same time, all the more junior people would never dip early. * The 'executive' level people never get involved in the day to day. Not really sure if it's normal or not, but we only have 15 people. * The bulk of the meetings are only targeted to about half the people. I've never once sat in on a meeting with the 'Director,' for example. * As part of industry functions, a lot of the senior people golf/go to baseball games/attend dinners literally 3 times a week or more. We never really get included in this. I know I'm a little green, but my coworker has 5 years experience, and it's basically the same for them. And based on what they do, the invites should regularly get passed onto them. * As for all of the above...trust me, it's not entirely merit based, or based on seniority. There is a lot of nepotism/and "old boys club" in this

It boils down to feeling like I'm stuck at my desk, both literally and figuratively.

However, I also understand that almost every corporation would operate like this. I get that it's not summer camp, and they don't owe me fun experiences. They can't just include everybody in every meeting. And they are treating me pretty darn well for my age.

At the same time, it doesn't really feel like I'm part of a team dynamic.

Should I just grow up? Or does it seem like my place has a slightly worse-than-average attitude towards junior employees and/or employees that aren't part of the inner circle?