Basically, if your natural lashes are reasonably healthy then yes eyelash extension is fine for you. Eyelash extension is done by attaching individual artificial lashes to your natural lashes. So regardless of your age group, if your lashes are healthy then eyelash extension is fine on you.
Main reason for eyelash extension is to create nice long thick looking yet natural lashes. With the right curl selection your lash artist could create different looks on your eyes and improve the shape of how your eyes appear.
For example, Asian ladies with long but thin eye shape could use eyelash extension to create the rounding effect.
However there are some groups of people who are not suitable for eyelash extension :
1) If your lash count is very low to an extent where you have almost no natural lashes.
2) If your natural lashes have been damaged, regardless of cause
3) If you habitually rub your eyes
4) Any kind of eye infection disorder
5) If you have undergone eye laser surgery in the past two years.
If you fall into any of these groups, we strongly recommend you spend some time to care for your eyes first. Wait until the problem improved, then come and get eyelash extension to make your eyes sparkle.