Bitcoin prediction has made many people missed calculate it at any given point in time. Base on your investment, already bought 1BTC, when was 17k, which was bought before the last Bull Run market, before it makes all time high (ATH) of 60k plus and you didn't sell, at least half of Bitcoin as of then and currently 1BTC is within 29k to 30k still in profits, while next Bitcoin many people are predicting 100k, base on that I'm very sure Bitcoin price will be more than 100k per 1BTC in the next bull run market.
After reaching its all-time high of 69k, it seems that the price of bitcoin dropped to 17k, which is likely when the OP purchased his bitcoin.
The OP's choice and plan will determine when to sell the bitcoin. I will advise the OP not to sell all of his bitcoin at once at any price, even if it's $100,000, since he was able to store it for such a long period of time. Instead, he should simply hold the remaining fractions and sell some whenever he feels it is safe to do so, perhaps when the price is above $50,000.
I was amazed that he bought at the very bottom price of Bitcoin which is around $17k. That's tough and I think it's not because of luck. I believe he had a good analysis in the market technically and fundamentally. Partial selling of Bitcoin if you're already profit with your investment is good but if you're good at analysing the market and you already tested it then it's better sell it all. I just wanna say that most of the time, the market will create lower low to fuel the price to create another high.