Blitz?
I recommend playing at a slower timer until you're a bit stronger. It's important to have enough time to think carefully about your moves. A blitz timer can make it hard to properly look ahead.
You'll know when you're ready for a faster timer - if you find yourself playing moves and waiting impatiently for your opponent to respond, then you're probably ready for something quicker. Until then, though, I'd say stick with slower timers and work your way up, over time.