05 Hard Sift

I have a 2005 SS Super Charged with 29,000 miles on it and today I was out driving around and stopped at a stop light right as I took off at a normal speed seemed like the tranny hit kinda hard in first gear. That something I should worry about or any Ideas what might have caused it? It may have happen a time or two before when I thought I just might have taken off on a patch of ice then caught traction but was 60 here today and of course no ice... Havent noticed it in any other gear..And I did check fluid and it was full... Hard Shift not sift Do you think its a tranny issue or could it be something else making it feel it was the tranny?