Don’t worry about your stomach rumbling.
Take a deep breath and learn to relax. You can do anything you wish. IF all you want or don’t. However you seem very anxious. You’ll be ok. IF and fasting is great in general. How quickly you get used to it is up to you.
Don’t stress yourself out. Do the best you can. Try to improve a little every day.
It probably depends on what your goals are and what you’re trying to achieve. For weight loss it may be much slower than you’d like, but there are health benefits to restricting your eating window overall.
It’s definitely a good start and as you get used to it you can always adapt and potentially expand from there if you feel the need. Reducing carb and sugar intake during your eating times will make IF infinitely easier.