I feel like I half-agree and half-disagree with this...it probably depends on your definition of 'art style'.
If you define it as 'your thought processes and tendencies as you conceptualize and construct artwork', then yeah, that's gonna be a product of your artistic evolution. You won't really 'find' it so much as you'll find yourself in it, and it'll feel different throughout your life.
But if you go by the colloquial definition of 'the way your art looks', then yeah, you can totally 'find' that, practice it, and mold it however you want until you settle upon something you like.
Or several somethings. ^^; As I frequently boast, I have a plethora of art styles, based mostly on different anime (and a few Western cartoons, occasionally). I absorb styles readily; chances are, if you think my art looks like [insert media] I was probably directly inspired by it, even if all I ever saw was a single screenshot or piece of fan art.
And as someone who 'finds' styles dozens of times a year...I think the key to solidifying an art style is getting it to a place where it visually interests you. Y'know, so your art-brain is engaged by it and WANTS to use it again and again. You should be able to look at your own art in that style and go "more please~"
For example, here's one I've been working on lately:
Same character; original design on the left, and new design on the right.
And you may be thinking, "oh, of course they like it more now that they made it more anime", however (a) I'm not ashamed to admit that I have a preference for anime art styles. I used be, and I used to purposely 'de-anime' my art to hide that shame, until I...well, grew up. ^^;
And (b) what I like most about this new style is actually the high contrast; the big, bold sections of pure black that specifically highlight the face. The super-thick 'KyoAni' eyelashes were the first thing I thought of when I went to update this style, and they ended up influencing the rest of the drawing.
I don't think I'm quite done developing this style; but it already looks vastly more interesting to me, enough to get me to actually work on the story this character belongs to for the first time in months. ^^ That's when you know you got a good one~