I hope that this proves to be a long and fruitful friendship/partnership for you two guys and everyone who worked with you on this deal. 

Try and establish a friendship with this ¨most trustworthy seeming¨ investor and maybe help them out with a flip so you can learn the business and hit the ground running when you turn 18. 

It doesn't have to be notarized or signed (just a simple email will do) but I have seen family and friendships ruined over not clearly understanding what they were getting into.If you can't get family to put up some money then go to some networking events and rub elbows with the investors that are doing deals.

Still do, it’s turned into more of a friendship than a business relationship at this point though.  

I joined bigger pockets to network, learn, create friendships and form win/win relationships.If you live in my area, let's meet up for coffee sometime!

She took advantage of your friendship and tugged on your heart strings. 

To me it's very hard to put a dollar amount or percentage on a true friendship.

I'm not a big fan of partnerships because those deals can kill friendships.

I would find projects with friends profitable in both friendship and monetary profit, seems like a big win win!

Friendship is Magic.