Should I come back to karate?

I really, really want to come back to karate.

The issue is I'm old now (I don't want to doc me, let's just say I am aged between 32 and 45) and my knees are not what they used to be and I also suffered a shoulder injury several years ago which led to an unstable shoulder and I don't have the strength to do a single push up now because that's the way my shoulder is now, there is no "working out to regain shoulder strength" in my case.

But I keep against, I want to be active again and I love karate... so I am very conflicted.

I am also a bit concerned of either ending being the sole adult among a bunch of kids (🤮) or being the weak dude among a bunch of hardcore guys who will see me as a wuss ("lol he can't do push ups and his knees are poop")

What are your thoughts ?