Hm. I think it will not be stable on my own opinion ,because the exchange is always fluctuating the market value .the more users of bitcoins ,the more tendency that bitcoin will be more become higher amount , just like our fiat currency is fluctuating .
That is the real world, and future will be like that for sure. So depends from definition of stability we can even now say that bitcoin is stabile.
Normally more people join safer currency will be, but bitcoin is going in good direction for now. That is most important thing, of course there will be problems some bigger then other what we can do is to be prepared for that, and not to quit on first sight of big problems coming.
If until end of 2020 bitcoin have at least double more followers ( and I expect more ) we will have chances for going really high.