National Guard V Reserves

I found out about the tuition benefits NG has over the reserves, after signing with the reserves. I ship out a month from today. I spoke to a NG recruiter and told me I can still switch over. That the day I am supposed to ship out, I don't ship out, and I'll get discharged. He said he can then get me in within a week. How true is this? Are there any consequences for missing my ship out date? Am I making the right decision? I'm planning on getting my Bachelor's here in illinois, does tuition get waived.? I know it's different in each state. Thanks in advance!