GBP/AUD short oppertunity 1st analysis

hi people this is my first attempt at analysis im thinking of entering a sell position
after maybe a pull back or a 3rd touch on the trendline i was unsure how to indicate take profit targets
so i just went off previous key prices and if it does form a pull back this week maybe use the new lower high as my stoploss

Please send me some feedback so i know im on the right track
and goodluck everyone

PS im only going to be entering my own trades on a Demo acc