There are a couple of issues you need to check out vis-a-vis Colorado and the Delaware contract situs.
1. Is Colorado a choice-of-law state? If not, Colorado will apply only Colorado law to the contract, with the exception that Colorado will not be able to apply its usury cap (or any other federally pre-empted laws), per the Supreme Court's Marquette decision.
2. Does Colorado view statutes of limitation as substantive law or procedural law? If it's the latter, Colorado will apply its own statute of limitations regardless. But courts increasingly have been viewing statutes of limitation as substantive law, which would mean that if Colorado is a choice-of-law state, the Colorado court should apply Delaware law.
I am not quite sure what your question is but in general there are certain premises we are wotrking with here that are uniform across most states:
1. A contract is generally held against the drafter so far as any ambiguities are contract interpretation is concerned. In other words, if B of A chose Delaware as their forum, they will probably not be heard to complain that you are in Colorado and its Statute of Limitations grants them more favorable terms.
2. When entering into contracts, parties are free to negotiate whatever terms they like so long as such terms do not violate public policy. In thsi case, chossing the forum and choice of law - here Delaware, is not against public policy, so would probably be upheld unless to do so would create a grave injustice. In the current climate, it is less likely many judges will have much sympathy for B of A.
3. Regardless of what I have said here, B of A will either sue you in Colorado or Delaware, and if you do not retain competent counsel in the proper jurisidiction, your chances of prevailing will diminish. So, if you go down the path it seems you are treading, be sure to hire a good attorney. Good luck!