Is it necessary to switch from a LLC to a C-Corp in order to offer equity in your company to an individual?

I run a pre-revenue start-up company. It was formed as a LLC and I currently have 100% ownership. Two months ago I received a $15K investment. The terms we agreed upon were convertible debt. His investment would turn into equity at either a specific amount of institutional funding or a certain time period, whichever comes first. Within the last two weeks, I have decided to offer equity in the company to an individual who will take us to revenue faster. I don''t have the money to pay him a salary so we spoke and I want to issue him equity. Am I able to offer him equity as a LLC or should I change to a C-Corp? We''ll hopefully getting more funding in the near future, too. Additionally, I want to know how the first investor''s investment will be effected if I give someone else equity? Thank you.