He/she sounds like a jerk!!
Plus your mutual friend isn't much better by relay that to you.
What that friend should have done is said "I think starlet has taken up the sport for some fun and exercise, from what I've seen achieving both and surfing well"
I hate when a friend doesn't back you up, even worse when they wait to see you next and kind of rub it in.

Stick it up em next session, get amped, go out try not falling to much, surf as hard as you can, hope he/she keeps falling off then to their face say "gee, never seen you fall off so much as you have today, maybe you should get a bigger board"
If you got something to say, then always say it to their face I reckon. Or even better if you don't have anything nice to say, then don't say anything at all.