WOW! 23... thats terrible buddy - definately get stretching. if your asymptomatic you'll be fine... actually come to that i got another mate whose 24 who has very tight iliopsoas and as a result has an increased lumbar lordosis (sway back). means he gets back pain when he runs though... hense he doesn't run. So guess your not alone.

You need to stretch them out - I assumed you were elderly so didnt say probably the best stretch. you'll be fine to try this one.
Do you know how to kneel and stretch your quads? get down onto your knees and put 1 leg forward. grab your heel of the leg thats on it's knee - amazing quad stretch... but what you can do is if you push into that front leg and lean backwards (or posterior pelvic tilt) you'll get an amazing iliopsoas stretch.
Who told you about your fixed flexion deformity - physio? get them to show you stretches and check your doing it right.
In the mean time... if you haven't got any symptoms then go for gold... beware your more likely to get back and hip pain.