Is a researcher with the same name in a different field likely to cause confusion?
First, you don't lose anything by adding initials. They will make it easier to search for your name in databases, until the day comes when academia has a unique/canonical researcher ID scheme in place.

If you have a middle name (or middle names), you can use those. If you don't, just choose a "pen name" by adding initials, chosen to make the combination of your name + initials unique (for now, of course… you cannot do anything about someone having the same name and starting to publish in a few years). I recommend doing that.

What can happen is that other people searching for your publications in the future might miss your first three papers. But if you have a publication list on your webpage (you have a webpage, right?), it's no big deal. Also, three seems like a large number now, but it will not always be that way.