Should I include as Estimated Income now, or apply as Qualifying Event later?

I’m in Pennsylvania and have purchased my health insurance individually since I don’t qualify for Medicaid but make too little to qualify for a subsidy on the Pennie marketplace.

My income will change around March due to inheriting some investments that will be changed to my name then and will make me qualify for insurance subsidies through Pennie. I am confused whether I should 1) apply for insurance on the exchange NOW and just include the new income in my estimate or 2) if i should wait until the investment is transferred into my name and then apply on the marketplace as a “qualifying event”.

My concern is if i include the new income on my estimate now, I don’t have proof / documentation YET that I will own the investments soon. Unless they would accept a letter that I am the beneficiary of those funds as proof although they aren’t transferred into my name yet. In general, does the marketplace insurance require you to provide proof of income at the time of application / very soon after, or could I have the insurance and provide the proof after the investments were transferred to me?