You’re not over thinking at all. Those are great questions. You definitely can get over reliant on a vibe to cum. But actually the same is true for most forms of stimulation, pillow humping, shower jets, etc.
The answers simple though. Mix it up! Use a vibe, love using it! But don’t do it all the time. For edging especially, use just your finger tips. Enjoy the connection with your body it gives you as you’re right on the edge. Use lubed fingers, lube, oil, soap in the bath, whatever. Make love, to yourself!
Let me add, buy a dildo. A nice, soft six inch dildo like this:

Check it out on lovehoney.co.uk (UK site) or lovehoney.com (US site) this:

http://www.lovehoney.co.uk/product.cfm?p=30709
Get it on lovehoney.co.uk (UK site) or lovehoney.com (US site)
That first one is just £6 in the sale right now!
So why a dildo? Firstly it feels amazing and will massively enhance your denial and edging experience. Secondly, only about a third of women cum from vaginal stimulation alone, and my feeling is that could be a lot higher if women actually took the time to explore and learn.
Using a dildo that size is not going to make you any ‘looser’ or make sex with you any less pleasurable, quite the reverse. It will mean you are relaxed and excited about that first time, and both of you will enjoy it all the more.
Learn how your incredible body works. You deserve it, and so does your future lover. Don’t get overly reliant on any toy, or porn or kink for that matter. Yep, you can even have too much denial sometimes! Learn to use your imagination. Your mind is the most important sex organ any of us are blessed with. That’s the one thing you can’t overdo.