Op, you are NBU, your birthday celebrations, your choice.
I have never involved wider family (who live/lived min 2 hrs away) in any of my birthday celebrations, just my immediate family and friends. I had an open house for 40th, went away with DH and kids at 50th.
DHs family on other hand, do like family celebrations for big birthdays. Started with PILs 60ths 18yrs ago. They booked cottages for us, SIL family, them and DHs uncle and family. It has followed on through other significant birthdays, sometimes cottages, or a hotel break, or caravan break. My side of the family have never been invited to these celebrations and neither has my SILs in-laws.
For DH 50th they all came and stayed close to us for a long weekend and we hosted for BBQ, sunday lunch out etc. None of my family were invited, I didn't get cross, his birthday, his family to invite. Would have changed dynamics considerably had my mum come (his family are fairly normal compared to mine!)
The latest one was for his uncles 70th and sisters 50th, a weekend cottage break, some wider family were also invited, but again, no 'inlaws'.
Just do as you want to and invite who you want.
We will hopefully celebrate silver wedding in 4yrs. PILs had a meal for family and friends in hotel for golden anniversary, SIL hosted a similar weekend for her silver. DH has already suggested similar for us, I am not bothered, as now my mum died and not close to brother, I dont have many on my side to invite, just a cousin and family who's DDs were my bridesmaids. I would rather have a really good holiday abroad for just DH and I and maybe kids too.