You don't have to be a Junior to start the recruiting process. Whenever you receive a recruiting letter you should acknowledge the contact by completing any forms they have asked you to fill out and return them promptly with a cover letter. The letter should be short, thank them for their interest in you as a student-athlete, let them know of your interest in their program, give them a spring schedule if you have one, and let them know where they might see you play in the future (summer showcase, major tournament, travel team, etc.). Good luck and congratulations on the early attention!