You should always use moisturiser, but I think the anti-aging creams should start being used in your twenties. There are products to suit each decade of the aging process. I'm in my 30's so I use products which suit 34 years of abuse!!
The best you can do for your skin is have a good diet, get plenty of rest, drink lots of water, dont smoke and above all use a moisturiser with a high SPF. Anti aging products are a waste of money.