Unfortunately, shimmer and glitter will make any fine lines or wrinkles stand out. If you are not a teenager, then you are probably quite aware of every little line around or on your eyes already. So do not emphasize them by adding shimmer to make them stand out.
If your eyes are starting to look more mature then you need to make sure you always wear a good eyeshadow base. This will help to smooth out the eye and give your shadow a good place to stay.
With a base in place, if your heart is set on a color with a slight shimmer then go for it. Shadows with a slight gleam or shimmer are safe and will not emphasize your lines or wrinkles. On the opposite end, using a shadow that is too matte can make your eyes appear dry ,cakey, and wrinkled. So with this in mind, choosing a slight shimmer or regular shadow would be ideal for a more mature eye lid.
A Final Suggestion:
Bright colors are trendy and fun, but keep the colors to a minimum if you are worried about defining lines and wrinkles. Bright colors can work like glitter on a mature eye lid.