No, not to me it isn't. She already told you she wants to be in on the choosing of a ring. If she wants another ring, she can get one some other time. Are you completely loaded with money? Spending a lot on engagement rings can be a silly road to indebtedness, when you have a lifetime of details to take care of. The ring is a symbol of intention to spend time being engaged and then, as you work out your futures together, assuming you do, then to get married. It's the life together that is important, not a fancy ring to start the planning period.
A lot of people skip the whole engagement ring purchase all together. You, on the other hand, are interested in having a proposal ring and an engagement ring and, I presume, wedding rings. Better to talk about what you two actually want your married life to be like.
This is just my opinion but some others are apt to agree with me.