Im 15, living in Australia. I am fairly fit and have been doing pushups, situps and have been doing 8kg dumbell weights for some time now (using many dif techniques). I do average 10 to 12 reps with 3 sets. Im also 5''7 and weigh around 60kg. Im not very skinny nor very large. I do have some muscle but i would like this to increase.

I want to begin bench pressing but do not know what weights to begin with and what to gradually move on to. Can someone please provide the most healthiest choice for my age but the most effective for muscle building.

I am also doing a sprint/run warmup before i begin any body building sport and also do a cool down session with stretches, i am also about to begin to consume protien shakes.

Thank You
If i have left anything out please tell me

If you are unsure about what range of weight plates to buy for your bench press, you could try going to a gym and seeing what your maximum lift is. Based on this you can work out how much weight you need to buy (eg. buy 40lb more than your 1 rep max so that you can keep adding the weight and increasing your max lift to see that you are making progress).
There is no specific amount of weight that you should be lifting for your age. It all depends on what you CAN lift. There's a lot of conflicting information about what rep ranges are optimal for increases in mass (which you seem to be aiming for), but the way I do it is to lift as much weight as possible that sees me failing at the 8-10th rep, and then gradually decrease the weight with each set so that I am always failing at the 8-10th rep as my muscles become gradually more fatigued. Make sure you read up on the correct technique for bench press, as it isn't as straightforward as lying down and pushing the bar up and down.

Protein shakes are good, but you shouldn't rely on them too heavily. Try to get one that has at least 20g of protein per serving, and take that as often as you need (but it shouldn't need to be more than 3 times a day). You need to alter the rest of your diet too to eat 6-7 meals per day, taking in more calories than you need as well as lots more water, and more of all the other food types like carbs and fats (good fats, remember). You can find all this info in details around the forum.

Would you say you have had a growth spurt in the past where you have shot up in height and filled out more over a short space of time? If so then you are probably ok to start weight training, because it can impact upon your growth if you start before going through the main stage of your growing phase as a teen.

Other people will be able to offer you more advice and I know if you look around the site in past threads and do searches on the things you want to know, that you will find everything you need to start training.

yeh thanks for that, ill also go there to help me on some good techniques.