Yeah, the MECIR can wait, you'll only need to keep it current which will set you back lots of $$$ as torque said. Cut your teeth on singles, get some experience and you'll find flying a twin no worries when the time comes.
When I did my CPL, instead of a night rating I did a SECIR. Was a good intro to IFR procedures and a lot cheaper to keep current. When the time came, instead of doing a renewal I did my initial twin endo and upgraded to a MECIR which was quite a simple process
Just something to think about anyway