Hi Ethan, ignore everything that was said on this thread. A lot of people are intelecualizing, moralizing, and complicating things. This can be much simpler than people are making it.
First off, it is kind of your grandmother to offer to lend you money at 5%. It shows she believes in you and wants to help you be successful. Thank her for that.
Secondly, you need more experience and understanding to become a good real estate investor. With a savings rate of $2000 - $2500 a month you have shown that you can manage your personal finances successfully so great job!
This would be my suggestion, continue to go to real estate meetups in your area and start connecting with other investors on a regular basis. If possible, invite a real estate investor to lunch each week and pay for their lunch. Ask them how they got started and what type of deals they are doing currently and what the numbers look like. After doing this for a few months and having gotten to know several (ideally 20 or more) investors, ask one of them that you felt most aligned with regarding the type of real estate they are doing if you can lend to them short-term on their next deal and if you could see the process of how they invest. Make sure your interest in the property gets recorded with the title company and then learn as much as you can about the process.
After doing this on 2 or 3 deals, you will be much better prepared to recognize a deal, how to get into a deal, what's important and what's not important in a deal, and how to make the deal profitable.
You are getting too much feedback on how people buy houses the normal way and get loans the normal way. Well your regular average person that buys a house the normal way gets rich very slowly if at all. Skip all of that. Learn how to find really good deals, and then get into a really good deal and turn that deal into a great place for you.
This is an idea of what I would do specifically if I were in your current situation after having dove head first into learning, networking, and participating in deals.
1. find a house from a wholesaler that is an older build but that doesn't need things like electrical upgrades or things like that. Look for a house that is around 1800 - 2200 square feet where you can change a 3 bedroom home into a 4 or 5 bedroom 2 or 3 bathroom home. This would make an ideal situation for a house hack/rent by the room situation which would exponentially build your income quicker.
2. Purchase the house with a hard money loan from a lender you met over the past year of doing deals with successful investors. Get a 90% or higher loan with rehab reimbursement draws where you can get money draws from the lender to reimburse what you spend on repairs. This will make it so you can recycle your rehab money and make it go much further.
At this time you should have an additional 20k - 30k in savings so you should be at about 50k or more to work with on the purchase and rehab.
3. After the repairs are complete and you have started renting the property by the room, look into either refinancing as a primary home or get a DSCR loan if the primary home loan lender is giving you a hard time.
If done well, you should be at only a 75% - 80% loan to value and you would have taken your $50,000 in cash and turned it into $100,000 or more of equity. You should be able to live in one of the rooms for free and cash flowing $500 or more a month on the property.
After doing this, go back to your grandmother and show her the deals you have been a part of, what you have learned, and the deal you put together. Then ask her if she would like to be your money partner on deals and go start crushing it. Outline the partnership expectations in paper, continue to build your support system, don't get over leveraged, and improve your craft.
I would encourage you not to use grandma's money at the beginning until you are already doing your own deals successfully. It makes it too easy to use easy money and it doesn't push you into finding really good deals. It would likely make you into a mediocre investor. So don't do that. Focus over the next year at building the investing rocket ship and then let your grandmother provide the fuel.