That would make this plane, at most, 11 years old.
Ever hear of retrofits?
“A 737 winglet installation is estimated to cost $725,000 for parts and a 1-week installation process costing $25,000-$85,000.”
https://simpleflying.com/why-boeing-build-737-without-winglets/
Here’s an older story:
“Delta Air Lines has announced an agreement with Aviation Partners Boeing (APB) to purchase Split Scimitar Winglets for its B737-800 and B737-900ER aircraft.”
https://aerospaceglobalnews.com/news/delta-to-upgrade-its-737-fleet-with-new-winglets/
The 737 variant with split scimitar winglets was introduced in 2014
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Those winglets are also available as a recent upgrade, so it possible the aircraft could be older.
https://simpleflying.com/delta-aviation-partners-boeing-winglet-deal/
The plane could be lots older than that. The first 737-300 with winglets flew in November 2002, with FAA certification granted in May 2003.