The kit come with the 12-40mm le , so if can get the extra lens will 40-150mm or the 45mm f1.8 lens be a better choice?
Dont rush into buying too many things when you arent sure what you need or like. That way you will spend alot of money unless you are rich or that few hundred or thousand of dollar means nothing to you.
slow and steady is always a better way to learn and discover. And the way to do it is to get the gear out and shoot more.. not buying more.
To ask 40-150 or 45 F1.8 which is better choice. That alone is a tough question. They are very different lenses.
40-150 gives you more reach than the 12-40. So if 40mm is not long enough. You may want to try 40-150..
different people learn and understand their want/needs and photography differently. No right or wrong.
Some people buy 1 lens at a time n see which is good for them. Some people just buy everything or few lenses and test them out. It's up to you which way you want it to be.
for me...
When i first started. I pick up the kit zoom lens and a tele zoom so I could cover more range. To know which i is more useful to me n which i prefer.
Before I look into short- medium prime lenses (typically fixed lens with F2.8 and below).
There are too many lenses out there. So dont rush. Take baby steps. Even if you are rich..and you could afford a dozen of the best lenses. You only have 1 pair of hands. Take it slowly.
Go with your budget and get what makes you happy. If its a hobby you have to be happy. Else...no point doing it IMO.
Good luck and shoot more.