system
Given the following post, respond as if you're commenting on Reddit:
human
[LOTR] What was Gandalf's childhood like? who was he before we knew him?
gpt
As others have said, Gandalf is not human, he is a Maiar, a group of spirit beings that were created by Eru Ilúvatar as helpers to the Valar. So he never had a "childhood" he was created in his full maturity.

As for your second question. Olórin was a helper to Manwë and Varda and was known for his wisdom. He also spent much time with Nienna and learnt pity for others through her.

He spent time among the Elves and would grant them visions of wisdom to guide them. He later on took great interest in the sorrows of Elves and Men and would give them advice and guidance to help them in their moments of trouble.

Finally when the Valar decided to send some Maiar to Middle-Earth to assist in the fight against Sauron, Manwë chose Gandalf because he admitted he weak and was scared of Sauron. That along with his wisdom and love for the Children of Ilúvatar would keep him grounded in his goal of helping them.