Seriously, it is not because the language that most projects experience performance issues... It is how efficient your code is. If you choose to spawn thousands of sprites on the same screen, all rendered with several 2.0 pixel shader effects, then not even the most core language is going to help your appetite.
Keep developing games, with time and experience you will learn to optimize your code to get the most from any engine that you work with. Most of those optimizations are engine independent, by the way - they are basic programming principles taught in schools.
Among the reasons for low performance, choice of the core language (whether interpreted or compiled) amounts for a very small part of it.