P.R.
Yes. It's easier to clip the fenulum (the thin membrane under the tongue than connects it to the bottom of the mouth) when they're younger and before it really affects their speech. The fenulum is sometimes too short and often goes unseen/ undiagnosed and is very important as it affects eating & speech down the road.
As a child gets older, the membrane thickens and the longer you wait, the more difficult the procedure becomes. I was tongue tied too and at five, it started affecting my speech, giving me a bit of a lisp or French-sounding accent, according to some. I had to have general anesthesia done, nothing major, but it's a lot easier when they're younger. Recovery was easy and my speech improved dramatically.
My baby was born with toungue tie too. In my son's case it was attached to the very tip of the tongue (extreme - level 1) which made it hard for him to nurse, though not impossible. He somehow was able to adapt using a nipple shield, but it took him a very long time to nurse (45 minutes or so).
Once the fenulum under the tongue was clipped by his pediatrician in a 5-second procedure, he was able to stick out his tongue and move it without any problems, and nursing quickly improved.
Most cases are not so readily visible - look to see if your child can stick out his tongue (for moms with younger babies, stick your finger in - sometimes they push it out). If the tongue doesn't pass his gum line, doesn't stick out past her lips, or if the shape seems odd (like a "w") there may be a problem.
I'm not sure what the process would be for a three year old but absolutely ask the doctor about it. By the way, the pediatrician who clipped my son's fenulum was experienced in this.