Introducing indoor kitten to outdoors?

Not sure if my thread belongs here.

I have a 4-month old kitten and I debate whether it's neccesary to have her go outside for its own sake - letting her see nature and learn new things.

At 2-3 months I have on just a few occasions let her roam outside close by my truck since she wasn't very mobile back then I could simply catch her and scoop her up again if she was getting too distant. But at this point she'll need at least a leash or something as I'm afraid she won't know what to do with a car coming in or other.

Tell me what you think.

I am beginning to believe she should stay indoors and never let her roam freely outdoors without me walking her on a leash. There are too many dangers - other animals besides other cats, worms, fleas, rabies, cars, mean people, tall trees, etc.. My kitten is nearly the size of her mother by now but still visibly a kitten with kitten mews. But I can tell that she is the type of cat that desires to go out and does not always want to be in the prison of her own home.

I totally agree with your instincts and believe you should make her a totally indoor cat.  You can make the indoors a lot more interesting for her by using creative "catification" techniques.  You can also build her a "catio" where she can be safe outdoors.  Here is a link to my own Pinterest page on "catification" where there are pictures of my favorite ideas other people have done. 
You can also harness train your kitten and talk her for walks.  I have several friends who do this.  There's an article on here about harness training your cat, and I'd be glad to send you my friend's written advice and a video of her walking her cat via private message if you like.  One reminder -- if she is walking outside, you will have to add a flea preventative to her regimen or you will be getting uninvited and unwelcome houseguests sooner or later.

Outdoor cats are at a tremendous amount of risk. They are susceptible to fights with other cats, confrontations with dogs or raccoons, and stepping in poo/dirty water that can give them diseases. Not to mention humans who might not want them hanging around.

Keep your kitty occupied with places to sit while watching out the window. My cat is indoor only and very content.

My two seem very happy indoors too.