Want to let kitten out but scared she won't come back

[BleddyHell]

We've had our kitten for around 3 weeks now and she's due for her jabs etc in a couple of weeks (for some reason the get couldn't fit her in any earlier). I really want to be able to let her out, I don't want a house cat, but how do I make sure she comes back?!
Thus may seem like a really stupid question but I've always been a dog owner, never cat, and my dog was easy to train...my kitten not so 😆 we live rurally so I'm just really worried she'll bugger off over the fields, never to be seen again (I let her out in the garden day before yesterday and she made an instant beeline for the field out front and I panicked and pit her straight back inside)

Our Girl is neutered and microchipped. we did not let her go out until she was a year old. at that age she was almost full size and a lot more able to defend herself if another cat bothered her, she could run much faster at a year old etc. I have done this with other cats too. she would not have a harness on in fact we bought several and she was like houdini. she's 2 now and enjoys going out.