Just be candid in your conversations with them. Tell them that you're relatively low-yeared in industry but offset that by emphasizing the mentoring you've done your current/previous jobs. I've had employers change the job description based on who they meet in interviews in order to justify bringing me in.
Collaboration: you should know what your coworkers are doing (more or less). Easy "I can prove I did this" mentoring can be something like a Lunch & Learn (teaching about advanced topics in C# or perhaps language features that would benefit the company if they would adopt it). The trendy term "thought leader" is what a mentor does but in a one-to-many instead of one-on-one.