My two top wisdom teath are healthy but are dropping down. Is it advisable to have then removed? What are the risks at my age?

If your upper wisdom teeth have super erupted I would recommend taking them out.  They are likely to be collecting plaque and developing large pockets between your teeth and gums.  As long as you are in good health you should not have any issues.  Consult with an oral surgeon and allow him/her to review your  health history to determine that you are healthy enough for surgery.  

I would recommend removing them only if they are causing discomfort or they are affecting how your remaining teeth come into contact.  They generally will drop down until they touch the gum tissue on the bottom.  If you're in good health, it should not be a problem to remove it if necessary.  Hope that helps.