thick?

[joe8]

what thickness are good for acoustic guitar strings if you are a beginner and only young

[stevie21]

If you're buying them in a shop rather than online then ask the blokey that serves you. I've played acoustics loads but I've only ever owned electric guitars and buy strings ranging from 9-42.

The lightest gauge acoustic strings that I've seen from a very brief look run from 10-48:
http://www.deanmarkley.com/Strings/Acoustic/BlueSteelAc. shtml

Lighter gauges are easier on the fingers and I'd say electric guitars are much easier to learn on as the neck isn't so difficult to get your hand around, the action (height of the strings off the neck) is often lower and strings are thinner & more manageable.

[j2buttonsw]

Agree with stevie, get 10s acoustic strings or even ball-end nylon strings. The thicker the string the louder the guitar but the harder it is to play. I also think electric guitar strings on acoustics sound poor (BTW, I only have 11s on my Martin). And stick with the acoustic and be a proper guitarist <insert smiley face here>.