Gradual hair loss can be caused by many things including hereity, Thyroid problems, Prostate problems, taking certain medications, topical skin preparations that "kill" the hair folicles, and manually pulling it out a few at a time, such as in twirling hair on fingers or pulling on the hair repeatedly. Continually having the hair pulled out, like with waxing, can reduce body hair over time. Some folicle damage can occur with radiation overexposure from constant tanning (usually in a tanning booth), or sun overexposure. Putting chemicals on the skin, either accidentally, or deliberate application can "kill" or damage hair follicles. This could be from working with chemical agents, spraying them and getting spray-back without washing, or using chemicals without regard to hazard. Many absorb through the skin and can make you ill, but can also damage skin and hair follicles.
Hi,The hair has not that much to do with your age as it does the amount of testosterone you have.Also depends on your family traits.Some familys have more hair than others.For instance if your father or grandfather has lots of hair you made also.You may however taken after your mothers side of the family that may not have lots of hair.As for as worring about It I would not.If you are under 20 you may begin to have more after the age of 20 as some men have a delay in there hair growth.As for as women that pefer men who are hairy or men who are not it depends on the female.I have seen just as many who like that as the number who dont.It mainly is a personal choice.
Personally, I think you should count yourself lucky. Most women adore the characteristics you describe. Fortunes are being made by salons who now perform more body waxing on men than they do women. I don't know your age, but sometimes it just takes a while longer for some men to get the same coverage of facial/chest hair as men their own age sometimes already have. Don't worry about it - the girls will love it! :)