First: My questions pertain to the existence of space, etc.
To your question IMO it depends on the definition of "civilization". We have good evidence that some form of "humans" existed as far back as 300,000 years much earlier than the ice age. However these were likely nomad individuals who roamed around without any "organization" . Post ice age we have strong evidence of humans that were organized into groups such as tribes, etc. This would compose what we recognize as "civilizations".
Anyway, that's my best /
