Firstly, welcome back to the section, diamondpearl876! Always nice to see members return. =)
Secondly - I quite like this beginning too. Very nicely written - the character of the Sentret is very clearly portrayed and I find it a neat choice of Pokemon as well. I'm also quite intrigued by this trainer who doesn't seem to know much at all about how to do things properly and yet can understand Pokemon speech just fine - so I wonder what his deal is and am looking forward to seeing more (as well as seeing what other Pokemon show up and what they are like).
Not much to fault here, really, although I did find the Sentret's tangent rambling a touch overdone after a while. I do wonder what it had done to be outcast by the other clan on that note... I didn't feel the first scene separator was necessary either, although there's not much issue with keeping it there either I suppose. The last line felt a bit disjointed as well from the previous and I wonder if the chapter would feel better finished without it, or at least some rewording to clarify that it was the way the sentret spoke was so cold (assuming that wasy what you had meant).
Mud clung to my face in response to disturbing it, causing the view before me to falter.
This sounded a bit odd - the first part I'm not sure that it sounds right that mud clung only because the Sentret 'disturbed it' which seems to be the implication from the wording, and I feel you could also make it clear that the sight was worsened from before the Sentret had been knocked to the ground as it doesn't seem that clear to myself.
Nice start, certainly - good luck with the rest of the fic!