I have seen both sides of the coin. A friend of mine used to switch companies frequently. He is making way more than his counter parts. Another friend who tried the same had his resume rejected multiple times quoting the he changes companies frequently and but his title remains the same. So he might be doing it for the money.
In conclusion it does not matter. There will be companies that will ignore your frequent switching and others that wont. However 3 switches in 4years is a bit much personally.
Getting into product gets tougher with experience. Also joining young is a good idea.
There are plenty of times that i have had second thoughts after getting a new offer. Excuses like everything is fine here. I am learning. Why should I leave. There are times i have stayed. All the promises of new projects coming and you will get to work on it are never kept. Its just that maybe you dont want to leave your comfort zone.
So I would suggest to take the offer.