England won the inaugural Arnold Clark Cup on Wednesday with a 3-1 victory over Germany at the Molineux.
Sarina Wiegman's side needed a win after Spain beat Olympic gold medallists Canada 1-0 earlier in the day to top proceedings.
Ellen White's early goal for England was cancelled out just before half-time when Lina Magull scored a stunning free kick.
However, with both teams pushing for a winner later on in the game, Chelsea's Millie Bright put the hosts ahead. Kirby scored England's third deep into added time.
"It is brilliant. For us in the past, it was a rocky road. For us to finally be on a journey together, we are on the right road," Bright said after the game.
"This is just the beginning. It wasn't pretty out there but it is another element to our game that we can win dirty."
England started the brighter of the two sides and were rewarded after just 15 minutes when White pounced on some uncertain German defending.
Kirby attempted a shot which was cleared but only as far as White who scored her 49th international goal with a low ball down the middle of the net.
Germany were able to get back into it on 43 minutes when Alex Greenwood gave away a free kick on the edge of the box.
Magull stepped up to take the kick and swirled the ball off the underside of Ellie Roebuck's goal and into the net.
Defender Bright found herself leading the England attack on 84 minutes when a deflected ball from Lauren Hemp landed at her feet and she smashed it into the Germany net.
Bright finished the tournament as joint top scorer with Spain's Alexia Putellas on two goals each.
Kirby then went on a solo run down the middle of the pitch on 93 minutes and slotted the ball calmly into the net.
"Today we weren't tight enough but then you have to be compact as a team," Wiegman said.
"When I came in this team had a lot of experience. The eagerness to commitment and wanting to learn is immense. It has been a pleasure so far.
"You want to keep all the players fit and in form at their clubs. Other teams progress too so it's hard to predict [Euros outcome]."