Most fast growing tech companies were in fact founded by people between the ages of ~28 and ~50 (and not in a garage), not by kids in garages. The kid in the garage founding a major tech company is a very rare exception. I can add a lot more names to this list:
Paul Graham (31, Viaweb), Jan Koum (33, WhatsApp), Brian Acton (37, WhatsApp), Ev Williams (34, Twitter), Jack Dorsey (33, Square), Elon Musk (32, Tesla), Garrett Camp (30, Uber), Travis Kalanick (32, Uber), Brian Chesky (27, Airbnb), Adam Neumann (31, WeWork), Reed Hastings (37, Netflix), Reid Hoffman (36, LinkedIn), Jack Ma (35, Alibaba), Jeff Bezos (30, Amazon), Jerry Sanders (33, AMD), Marc Benioff (35, Salesforce), Ross Perot (32, EDS), Peter Norton (39, Norton), Larry Ellison (33, Oracle), Mitch Kapor (32, Lotus), Leonard Bosack (32, Cisco), Sandy Lerner (29, Cisco), Gordon Moore (39, Intel), Mark Cuban (37, Broadcast.com), Scott Cook (31, Intuit), Nolan Bushnell (29, Atari), Paul Galvin (33, Motorola), Irwin Jacobs (52, Qualcomm), David Duffield (46, PeopleSoft; 64 Workday), Aneel Bhusri (39, Workday), Thomas Siebel (41, Siebel Systems), John McAfee (42, McAfee), Gary Hendrix (32, Symantec), Scott McNealy (28, Sun), Pierre Omidyar (28, eBay), Rich Barton (29 for Expedia, 38 for Zillow), Jim Clark (38 for SGI, and 49 for Netscape), Charles Wang (32, CA), David Packard (27, HP), John Warnock (42, Adobe), Robert Noyce (30 at Fairchild, 41 for Intel), Rod Canion (37, Compaq), Jen-Hsun Huang (30, nVidia), Eli Harari (41, SanDisk), Sanjay Mehrotra (28, SanDisk), Al Shugart (48, Seagate), Finis Conner (34, Seagate), Henry Samueli (37, Broadcom), Henry Nicholas (32, Broadcom), Charles Brewer (36, Mindspring), William Shockley (45, Shockley), Ron Rivest (35, RSA), Adi Shamir (30, RSA), John Walker (32, Autodesk), Halsey Minor (30, CNet), David Filo (28, Yahoo), Jeremy Stoppelman (27, Yelp), Eric Lefkofsky (39, Groupon), Andrew Mason (29, Groupon), David Hitz (28, NetApp), Brian Lee (28, Legalzoom), Demis Hassabis (34, DeepMind), Tim Westergren (35, Pandora), Martin Lorentzon (37, Spotify), Ashar Aziz (44, FireEye), Kevin O'Connor (36, DoubleClick), Ben Silbermann (28, Pinterest), Evan Sharp (28, Pinterest), Steve Kirsch (38, Infoseek), Stephen Kaufer (36, TripAdvisor), Michael McNeilly (28, Applied Materials), Eugene McDermott (52, Texas Instruments), Richard Egan (43, EMC), Gary Kildall (32, Digital Research), Hasso Plattner (28, SAP), Robert Glaser (32, Real Networks), Patrick Byrne (37, Overstock.com), Marc Lore (33, Diapers.com), Ed Iacobucci (36, Citrix Systems), Ray Noorda (55, Novell), Tom Leighton (42, Akamai), Daniel Lewin (28, Akamai), Michael Mauldin (35, Lycos), Tom Anderson (33, MySpace), Chris DeWolfe (37, MySpace), Mark Pincus (41, Zynga), Nir Zuk (30, Palo Alto Networks), Caterina Fake (34, Flickr), Stewart Butterfield (31, Flickr), Kevin Systrom (27, Instagram), Adi Tatarko (37, Houzz), Brian Armstrong (29, Coinbase), Pradeep Sindhu (43, Juniper), Peter Thiel (31, PayPal; 37, Palantir), Jay Walker (42, priceline.com), Pony Ma (27, Tencent), Robin Li (32, Baidu), Liu Qiangdong (29, JD.com), Lei Jun (40, Xiaomi), Ren Zhengfei (38, Huawei), Arkady Volozh (36, Yandex), Hiroshi Mikitani (34, Rakuten), Morris Chang (56, Taiwan Semi), Cheng Wei (29, Didi Chuxing), James Liang (29, Ctrip)