Finishing MSc at 27 in the UK,

I completed undergrad B.Sc at 21, 3-4 years teaching overseas,

Considering a PhD and applying but apparently it takes 1-2 years to get a phd position in the UK/EU/USA, then 3-4 years to complete it.

So I'll likely be 32-35 by the time I finish,

The average age for phd completion (OECD stats) is 27, So I'm 3-5 years behind...

tl;dr is starting a phd 27+ suicide tier?

How bad is ageism in academia/science against slow/older applicants?

I'm guessing by the CV's of tenured academics/scientists that they all finished their phd's below 25. Are there any who started later?