Transferring offline progress to online 360 to one

It’s asking if I want to go online and forfeit 2,463,397 credits or no and continue as a default spartan. If I choose the first one will I still have all my progress? This is for halo reach. It took me 8 years to get to general grade 3 on an offline account

Sorry OP, but if you take your account online then it’s going to be reset for online play. I can’t recall if you get to keep your stuff offline (I think you can), but for playing connected to Xbox Live you need to start the grind again
http://halo.bungie.net/news/content.aspx?type=topnews&link=Reach_FAQ#_3

> Going Online for the First Time
>
> If you initially earn offline Credits and then take your profile online, there will be a onetime check to see how many Credits you’ve acquired. If that amount is over 26,250, you will need to forfeit some Credits. This check is in place to ensure a level playing field and to eliminate foul play.
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> If you choose not to authenticate, you can still play online, but you will subsequently appear as a default Spartan with a default emblem and colors. If you want to change your mind, simply reboot your console and upon your next foray into online matchmaking, you’ll be prompted again.
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> If you have purchased shiny new Armory items, the authentication process may reclaim armor pieces in order to bring the Credits balance into a positive state. The end result is Armor + Credits = 26,250. No more, no less.
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> If you have less than 26,250 lifetime Credits earned when you go online for the first time, you won’t have to worry about any of this complicated math.
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> Note: Authenticating Credits does not provide any personal information to Bungie. It’s only used to track Credits per gamertag.
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> Once you authenticate your Credits with our online servers, you will not see the Credit loss dialog ever again (unless you decide to create a new profile). If you go back to playing offline, the game will simply cap you at 1,000 Credits per day until you reconnect to LIVE. If you are playing while connected to LIVE, there is no cap and you can earn Credits to your heart’s content.