Private lending advice

[Nathan Ruffrage]

Hey Oh friends! 
Investor here looking to dip my toe into private lending to another investor. 

Deal- Wholesaled property under assigned contract and buyer looking to borrow 130k at 11% for 4 months from me to finalize the deal and get the property refinanced. I will be in first position on the note.  Buyer is a seasoned investor with a good track record. Property is something I would be glad to add to the portfolio. 

My confidence areas and experience are in LTR, STR and BRRR but not private lending.

Any advice on what I should consider or create in order to protect myself or add value to the deal. Thanks!