Your luteal phase length sounds normal to me. The norm is between 10 and 16, with 14 days being the average.
People generally take B6 and vitex to lengthen their LP, if say it was under 10 days.
Cycles do change over the years, usually becoming longer in your 30's (sorry I have no idea if this applies to your age!).
I wouldn't be worried about it, but it doesn't hurt to ask your GP