Can my front two teeth be shortened with the level of other teeth?

From the picture this looks to be around 4 mm of difference between the tip (incisal) position of your central incisors to your lateral incisors.   Reducing your central incisors to this degree will expose the dentin in your tooth and could make them sensitive and more susceptible to decay etc.  I would not recommend doing that. 

It would be very acceptable to shorten your two front teeth.  I would recommend doing a bonding repair to the fractured lateral incisor on your left side as well as remove 1.0mm from the two front teeth.  It should take about 5 minutes to remove and smooth those teeth.  The technical term would be enamelplasty.   I hope this helps.