You can improve your handwriting at any age! yes. All you need is a Pen/Pencil , a notebook and 10 minutes of your daily time. The basic of handwriting is dependent on three things:
1. The way you hold the pen ( the number of fingers you use and the place of holding the pen)
2. The amount of pressure you are applying on the pen
3. The angle at which you are holding the pen.
Some people hold the pen very near to its nib. In this case the writing becomes somewhat slower and clumsy. It is always a good practice to hold the pen slightly higher from its nib. Secondly it is convenient to apply little pressure on the grip ,instead of holding it very tightly. By doing that you can move your hand faster and with ease. Finally the angle of holding the pen! It is convenient to slightly tilt and write rather than writing vertically. If you write vertically then it constricts you to a single font, but if you are writing at some angle you can vary your font !
Hope this helps... Happy writing!