It is dangerous to have a fixed TP. It could be acceptable if you fix your SL base on your risk capital but that should not necessarily be applied to TP.
You need to go back to your system and do some work. Find a way to make trailing stop work for your system. This is a trade war between your losers and your winners, how sure are you that your winners will beat your losers after 6-12months in terms of statistics?
That’s the reason leaving your winners to run is very vital for profitability in the long run. Assuming your 15pips TP is hit, work on your system in such a way it will be able to lock some profit or break even why you keep your trade on.
When it move from 15pips to 30pips you can then lock 10-15pips and let your trade keep going. Work on your trade to achieve this, it is possible. There is a way you will balance your system to accommodate trailing stop, you will get stopped out at a loss, break even or small profit but it will be 1 in every 10 trades. If you are finding it difficult to achieve this, you can share your trading system and members will put heads together to help you out.