Firstly, we need a picture of your crown- clearly your hair has receded a little, but that doesn't mean you'll definitely go bald, it could be a maturing hairline... From the looks of things, this could well be Male Pattern Baldness, but you might see no further recession for 10 years, it's a disease that affects everyone so differently. The trouble is, once the hair completely disappears from your temples unless you are the lucky minority, you won't see it come back no matter how hard you fight. With this in mind, would you consider minoxidil? You can directly target the places causing you concern, and there's a good chance you'll see some regrowth if it is male pattern baldness. Further, you don't need to worry about any side effects of finasteride.
What I would say is that if it is male pattern baldness, sooner or later you are probably going to have to come to terms with the fact that you'll need to go on Finasteride if you want to keep the hair loss to an absolute minimum... or even completely retain your hairline. Finasteride does exhibit side effects in a small number of people (let's be fairly generous and say 5-10% experience some degree of side effects, but many will accept this as being better than losing hair) and of them, a far smaller percentage will experience any long-term side effects once they come off. Realistically the chance of your life being significantly impaired by the drug is incredibly slim, ignore what others say.
However, waiting a few years and sticking with Minoxidil will buy you some time, and maybe more reassuring evidence will surface about the safety of finasteride, meaning you'll be more comfortable taking it 3 years down the line (for example) when you need to.
The fact is, combining minoxidil and finasteride into your daily routine needn't be too expensive if you find the right vendor, and there's a good chance your hairline and hair count will be greater than what it is now 5, maybe even 10 years down the line.
-What about after that?
Well, you'll be around 30 most likely when you see a recession developing again (of course some men have been on it for 10-15 years and experienced little, if any further loss). At this point, many of your friends will also be exhibiting hair loss so it won't be as daunting.
Also, there are so many potential treatments in the pipeline that in 10 years, to have no alternative treatment would be unlikely. I would hazard a guess that by 2020 there will be selective implementation of RCH-01 therapy (have a look at it if you don't know what it is). So you're buying yourself time.
Finally, remember that it's better to try and retain the hair you have than losing it all and saying "i'll wait until a better treatment comes along to give me back my hair" because this cuts down your options, and we might get a cure for keeping/protecting hair long before we have one for rebuilding it from nothing.
Go and see a dermatologist.
