Loop freezes game on load

[MoreUmph]

Im trying to make a simple addon that switches the action bar if a player has certain spells learned. Dont ask

Without a loop, it works fine, upon reloading the bar switches successfully, but with the loop the game
becomes unresponsive upon load

I look up the 'OnUpdate' event but it says I need a frame to update and bunch of other things, the code I've tried doesnt work and is just too excessive for my needs

Would appreciate a point in the right direction

local looping = true, a, b, c, d
while looping do
  a = IsSpellKnown(72, false)
  b = IsSpellKnown(73, false)
  c = IsSpellKnown(74, false)
  d = IsSpellKnown(75, false)

  if a and b and c and d then
    ChangeActionBarPage(2)
    looping = false
  end
end