Can my wife get half my rare coins in our divorce if we have a prenup?

I have a prenuptial agreement signed by my wife and we are now in the middle of a divorce. The prenup says I keep all of my antique coin collection regardless of whether I bought more coins after we got married. My wife’s lawyer in Dallas just filed a paper saying my coin collection needs to be appraised and she wants half the value. I asked her what about the prenup and she said it’s no good because I forced her to sign it and she didn’t have her own lawyer. My lawyer drafted the agreement and my wife had plenty of time to look it and take it to a lawyer if she wanted. I never forced her to do anything. Is my prenuptial agreement valid and can I enforce it against my wife so I can keep my collection?