I have a stammering problem since childhood, but now it is increased because of stress and mental pressure. can this be completely eliminated?

With Proper Therapy?: Yes it can be eliminated by assessment and treatment by a certified speech/language pathologist while there is no complete cure but there are several treatment options available which help people to control their speech even at age of 34 there is a chance that with proper trainng it can be improved consult a certified speech;language pathol;ogist, it is never late it does become difficult as u age.

Yes, but..: As you have noted, stress can increase symptoms. It takes a good speech therapist and/or a psychologist to work together to teach you how to control your anxiety other than with speech problems. It takes hard work and practice, but absolutely can be conquered. Go into treatment with realistic expectations, though. It is not going to happen after 1 or 2 sessions - it takes time and patience.