Current price is $26 , is now a good time to start investing or is it likely to drop to around $20? I want to buy and hold for a few years at least.
Buy now at the current price regardless of whether it will go up or down later on after you bought. You said that you want to hold for a few years therefore any price today should do. You actually already answered the question.
It's good that you now hold some instead of waiting for more price decrease. If you anticipate that it will go down more, then buy by batches slowly.
We will never know the result until we do it in actuality.