help please

After much reading and deciding, i decided for my first grow im just gonna grow some plants out in the back, maintain them properly but trim amd maintain size and basically wait it out untill i notice its started to flower the just count down the weeks untill it seema ready.
Is this viable or do you HAVE to grow according to certain months n shit.
Or is this completely agreeable just to grow a batch routinely for own supply.

Southern Hemi your plants if started now would grow until the time of the days were around 12 hours...
What are your days length in time now? As days get shorter that would possible start your bud time as length of day nears 12 hours...

The suns coming up round 5-6am and setting around 7-8pm
And the strain im growing is an autoflower if that helps.

with the autos you can just throw them outdoors they will start to flower regardless of the time of year. if your in the southern hemisphere your all good as long as it is warm enough. there is no need to even worry about natural ganja harvest time (fall) they should start to flower on their own.
just get a book or read up on best time to harvest when they are ready.

obviously if it is winter or to cold they will not perform but otherwise all good