The German was offered an 18-month deal to replace Frank Lampard, with an option for an extension.
And Tuchel says he had worries if he didn't hit the ground running at Stamford Bridge.
"I would say it affects me because everything affects me - but in a very positive way," said Tuchel
"I was worried about that in the beginning. It was all done in 72 hours so I didn't like it at first. It was like 'They don't trust me? What is this? 18 months?'
"I have to leave this country, leave my family behind, it is not so easy to jump in there. What do they think? They are so many points behind place number four. So maybe we don't make it, which is still possible we don't make it because still it is a hard race and then it is easy to sack me again.
"Then after some minutes - it was a matter of minutes – it was like 'what does it change anyway?'
"I took it off my shoulders. If I am good, if they like what I am doing they will make me stay. If I am not good, if I don't have results, they don't like me, they will sack me anyway.
"I could have a five-year contract and they will sack me anyway. So why worry about it?"