Pre-mining is frowned upon though is it not?
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I am working on a project that we will take ICO
It is, and so is making an ICO.
Say you wanted to create a Crypto currency that was totally mined and not pre-mined would the coin be more popular or does it make no difference?
It makes no difference because it will just be another ICO token among millions of other ICO tokens that no one has ever heard of or cares about.
The time it would take to mine X number of coins of a yet to be created altcoin is entirely dependent on the parameters you set for that altcoin. It will depend on the difficulty (the Proof of Work target parameter that you begin with), the target block rate, the hash algorithm, etc.