It won't rule you out, but you'll be going up against people with 2-3 more years of experience (on average) and, more importantly than the amount of time, more experience leading others, tackling tough problems, etc.
You'll need to be really tight on your story for why an MBA now. I understand your thinking re: ROI, but you're talking about a decision that will affect the rest of your life, so one or two years more of post-MBA career work won't make much of a difference in the long run. Hopefully you'll have terrific recos that highlight your maturity and emphasize the theme of "this person is ready NOW."
Re: your aunt, that won't help you very much. Learn from whatever insight and contacts that you can from her, but don't think that dropping names in your app will matter one way or the other.
Scott
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Co-Author, Your MBA Game Plan