That should be fine - I have 10.8 on a 2008 MacBook (vice MacBook Pro) of similar vintage. Anyway you appear to meet the spec here:
OS X Mountain Lion - Apple Store (UK)
You don't need to worry that it won't cope - as has been said the OS has got better over time. There will be the usual frustrations which seem annoying at first but you soon realise that most changes are for the better. I think there was a reversal of screen scrolling direction in one of those updates, to match the way iOS devices scroll, which was one of those that you had to get used to. (Now I wonder how I coped without it).
The problem might be that you have to have Lion (10.7) installed to upgrade to Mountain Lion (10.8) which is a pain. I don't think you can go straight from Snow Leopard (10.6) to ML. Someone may correct that. They are not expensive, even if you have to buy both, it just takes twice as along. I recently started afresh on an old iMac and had to (re)purchase Snow Leopard just to get it back to Lion (because I'd lost my SL disc).
Other than time, the update process is simple. You lose nothing, settings and passwords etc remain, no starting again. Although it is obviously a good idea to have everything backed up just in case.