To be entitled to veteran benefits, and to be considered a veteran you need to have been activated on federal service continuously 90 days or more (other than training purposes), and discharged under honorable conditions.   

Or

Served at least twenty years retiring you under title 10 of the United States Code shall be considered a veteran. 

If you were not activated for 90 days or more you still  have some benefits opportunities.  

• Educational Benefits (Use it or lose it - check your dates to ensure you did not allow these benefits to expire).   
• Service-connected disability if you were injured while serving.  Proof of event or injury needs to be present in military medical records.
• Military Honors
• VA Guaranteed Home Loan (If you have six solid years between the National Guard & the Reserves combined. Need to provide a NGB22 & NGB23 (retirement points).  
• A National Guard individual who has a service-connected disability rating, from an injury in basic training and has never been federally activated except for basic is eligible for burial benefits (21P-530 Application for Burial Benefits).
• Carry & Conceal Permit ($50 fee and proof of completing basic training, along with total time in service - your DD214 needs to be recorded within the county in the Record's Office)
• Even though he/she has a service-connected disability rating he/she is NOT eligible for a grave marker because he does not have a 20 letter from the National Guard, or was activated for federal duty (90 days or more) other than for training purposes.  

What you will not be able to apply for:  Veterans License Plates, Veteran - Driver's License Status, Veteran's ID Card, Headstone or Marker, Iowa Trust Fund, Military Property Exemption (unless you have a 20 yr letter or was federally activated for 90 days or more), and VA Pensions.

VA Health Care (Minimum Duty Requirements - Most Veterans who enlisted after September 7, 1980, or entered active duty after October 16, 1981, must have served 24 continuous months or the full period for which they were called to active duty in order to be eligible. This minimum duty requirement may not apply to Veterans who were discharged for a disability incurred or aggravated in the line of duty, for a hardship or “early out,” or those who served prior to September 7, 1980. Since there are a number of other exceptions to the minimum duty requirements, VA encourages all Veterans to apply so that we may determine their enrollment eligibility). If you are entitled to service connected disability, and was never federally activated this rule does not pertain to you.