Does age really matter how well you write? How did you start out when you first started writing?
Not age
in itself, but statistically, younger authors are generally less experienced and less experienced authors are generally worse at writing than more experienced ones, which creates something of a correlation. It's not a perfect correlation, though - writing or aspects of writing can come more naturally to some people than others, so they may get the hang of it before somebody who has more experience, and some people start young and thus have more experience when they get older than people who start older.
If you're young and feel like your writing isn't as good as other people's, it may be because of your lack of experience, or it may just be something that doesn't come as naturally to you, but the answer to that is always just writing more and getting more experience - you should never worry about whether other writers are better than you when they were your age or had your amount of experience.
Either way, I started out writing hilariously awfully. When I was describing my first story in my first post here, there wasn't much paraphrasing. There was literally a page that went "But soon it became apparent that a rock had gotten stuck in Faxi's eye! But soon it fell out." Meanwhile, my first Pokémon fanfic contained a lengthy explanation of why my ridiculous legendary bird had no weaknesses, followed by a realization that oh wait actually it did. And battles that consisted of the Pokémon making their cries at one another until the narration declared that one of them had fainted.
How do you open stories?
Usually the opening is one of the first things to come to me about a story, so it's not that I consciously go about opening my stories in some particular way. Generally I've started by introducing a character and the general theme of the story, I guess, but that's about as generic as you can get.
Can cursing get in the way of the atmosphere in the story?
Any element of tone can get in the way of atmosphere when misapplied, but that depends on what the atmosphere you're actually going for was in the first place. If you're going for something fairly gritty and realistic, and the story happens to have characters who would swear frequently, then by all means have them do so - but if they start doing it to an unrealistic degree, then that doesn't work in your realistic atmosphere. On the other hand, if you're going for a crass comedy kind of thing, then swearing can be pushed to ridiculousness and still work fine in that atmosphere (which isn't to say it's automatically funny or whatever, just that it wouldn't be out of place). And conversely, if you're writing something similar in tone to something like the Pokémon anime, a lot of swearing would probably be out of place. Most of this is common sense.
I don't think swearing in itself is ever a problem - only when it clashes with the story it's in or the characters whose mouths it comes out of. It's your choice as an author whether you want to include it in your work, of course, but I don't think "Thing X that's common in real life shouldn't be in fiction" is ever a justifiable statement to make.
Negrek said:
about the only really significant thing I wanted to say anyway was to tell Dragonfree that omg I totally remember that kadabra 'fic. It had to do with you being angry about the bumping rules in a spriting forum somewhere, didn't it?
Not bumping - they had a rule that every post had to be more than three words and closed my sprite thread because I posted some sprites without also including comments of four words or more along with them. For some reason I felt like being argumentative about this, so I complained and asked if they really thought a post adding artwork to an art thread is spam if it's accompanied by a message like "Gold version Misdreavus", but not when accompanied by, say, "This is a Gold version Misdreavus". The mods answered basically "Yeah, because the rule says posts have to be more than three words." So I ragequit and wrote that.
Negrek said:
(From the same era, I also remember The Trainer With No Dreams, or whatever it was called... too bad you never decided to continue that; it could have been cool!)
I might! Someday. Maybe. I had some kind of neat ideas for it and if I were to write another trainer fic, picking up on that would currently be the main candidate, but meanwhile I have all this finishing TQftL/Morphic rewrite/Morphic sequel/inevitable Morphic sequel rewrite/more TQftL rewriting/DAVE AND MIA DISCUSS EVERYTHING to do.