Once the Game is Launched it doesn't respond for several minutes

Once I press the PLAY button on my Minecraft Launcher and the actual game starts to load my Minecraft screen shows the Mojang logo and in the corner it says '(Not Responding)'. I have to wait several minutes for the game to fully come on. This has been happening since I started playing Minecraft, but I did not know about this website and I wasn't sure whether it would count as a bug. I don't know if anyone else is experiencing these issues. If anyone knows how to fix this or whether it is normal for the game to do this please let me know.

Kind Regards

DogGirl108