[gmhendersonme-com]

It’s a pretty good stretch…much better as you move up to the 5th and 7th frets. My advice would be to get your index finger as close as possible to the fret, and to press as lightly as you can to still have the 2 strings ring out ( we all tend to press way too hard when we “barre” more than one string ). Practice on the higher frets where they aren’t so far apart and then move back to the 3rd fret gradually. Good luck !