Cameroon and I predate Newtonian Gravity (v48) so I'm going to say like 43 or 44 since I remember updating a few times before the update with newtonian gravity
Started with version 35 or so, first forum post off July 2010, relating to things before TPT v43, where light refraction was first added. From Estonia.
Australia, I have been playing this since the first version with plants, it was circulating about a lot around school. I only found the actual website for it about version 35.