If your compression is good/within spec and you are not riding the bike into the ground and you change oil regularly , 35 hours is not much unless you are racing Pro class , to me it is just starting to break in good , you should be able to get 100 hours on a piston (average joe weekend warrior) , I have probably 150 on my 02 since last piston change , which is only the 2nd piston since I have owned it since 08 (don't have a hour meter , but one of the guys I regularly ride with does and I use his time to estimate mine) , my last piston was fall of 2016 and I track ride almost every weekend (well actually I ride almost every weekend since 2018 due to some health issues I had that prevented me from riding 2017)
If you use good oil , especially Synthetic , you should be able to run 50 hours minimum even if amature racing , my friend with a KTM , has over 300 on his 13 450SX on the same piston , and tore it down , and ended up just replacing the head gasket and is still running the same piston ..... good oil and changing it before it gets real dirty is the key to piston life , and stay off the limiter....... Remember , the "recommendation" in the manual is just that , a recommendation , and for serious racing , not what the average rider does , and is only a reference guide , not mandatory , if you are not abusing the bike like a Pro would , just pay attention to the compression , if you notice a drop and its not valve related (you can do a Leak Down Test and it will tell you if air is getting by valves or the rings) , then its probably time for a piston .... If you tear it down and the skirt does not look like the pic below , then you are probably good
Top piston is worn , Bottom is used but not worn: