No worries man, i know you are new and there is a shit ton of different terminology to deal with with bikes, a longer stem makes more sense to me now :D
Generally speaking handle bars are made with different amounts of rise to lift the bars upwards as you can see here on my bike which has a lot more rise than you -

It isn't unsafe or anything like that to mount them the other way up I just can't say I have seen it done before and obviously this will change your position on the bike and comfort levels more than you would think, even mm in difference in all things like handle bars, stems, seat position etc can make drastic differences to comfort, especially over long distances.
Are the bars entirely straight across from left to right? Most bars usually also have different amounts of sweep which is the degrees that the bars go back and up as you can see here on mine -

They aren't entirely straight and that sweep should be towards you rather than away.
One post you said your hands / wrists ached for a bit. Whilst this is normal as you aren't used to riding a bike it can also be due to bar positioning as you could be adding extra force at points where you don't want it due to a combination of how your bars are positioned and how you use them, beyond this sometimes this can result in numbness in the hands too which obviously you don't want.
"Bike fit" which incorporates everything from handle bars to stem length to seat position, tilt and height can all have a lot more drastic impacts on your body than you'd think even through small adjustments and is something you should tinker with to try and find the best position for you. You can pay to have one done professionally but it would probably cost more than your bike is worth to begin with so at this point I'd avoid that.
I would be inclined to adjust your handlebars so that the rise is facing upwards, if you have any sweep have it so the ends of the bars are closer to you than the center rather than further away before you start buying new stems and things like that as they are all things you can do for free.
If you change it and don't like it you can always switch it back to how you have it now, it looks weird to me but it isn't like it is dangerous and your comfort is more important than how it looks.
I have spent the last year tweaking my current bike trying to get it in the perfect place so it definitely takes some time. Make small adjustments, go for a longer ride and then assess how you feel. I realise it will be harder for you not know bikes in general as well due to being new but you can still tell what is and isn't comfortable and if you are getting any pain in places like knees and wrists.
Good luck with this new journey and enjoy it!