My child loses his both lower central incissors 5 months before his 5th birthday, new teeth starts developing in it's place.is that too early for his age.no teeth decay history .any cause for concern?

No cause for concern. Secondary teeth will erupt earlier in some children, later in others. Let your child's dentist monitor any crowding and have an orthodontic consultation if indicated.

I think that your child will be okay. Losing the teeth might be a little early, but there is no set timetable when teeth can be lost. Please consult with Pedodontist, a Specialist in Dental Medicine for children, for a more comprehensive diagnosis and guidance.

Although a bit early, it's well within normal limits. As with all children, Standard now care is that ALL children have their 1st Orthodontic examination (usually complimentary) at eruption of the first permanent tooth, but not later than 7th b'day. It would be prudent to have your child seen by an Orthodontist.