When i am starting my bike when cold it takes very long time to start. i have to keep pedalling for like 5 mins and then it slowly starts giving a few kicks until it is finally running. once it is warm it is easy to start.
Engines need additional fuel and/or less air when cold in order to start. If you never use the choke on a cold start it will act exactly as you describe. Choke on to start, once it starts you can try turning it off, but on cooler days it may need to stay on for a minute before being turned off. Once the engine is warm, no choke is needed.