Earl, 19, finished 72 holes at 2 under, and four more players were at 1 under right behind her. That included two GB&I Curtis Cup team members in Lily May Humphreys and Shannon McWilliam.
Early bogeyed the last hole in a final-round 73 and faced an anxious wait to see if Rosie Belsham could catch her, but in the end Early prevailed.
Scotland native McWilliam also moved up the leaderboard with four birdies in her opening 15 holes in the final round but a bogey at the last meant she had to settle for a 69 that left her one shot short.
England’s Sharna Dutrieux made her move in the morning with a 69 and she looked as if she would maintain her run when she fired five birdies in seven holes from the fifth but four dropped shots over the closing stretch saw her also come up one shot short in the group in second place.
Belsham knew she needed to birdie the last to force extra holes against Earl, but she couldn’t pull it off. A final-round 74 also put her in the group at 1-under 287.
On a day when several of the more experienced competitors made a move up the leaderboard England’s Isobel Wardle was 7 under for her first 16 holes but bogeys at Nos. 17 and 18 contributed to a closing 67 and left her in a share of sixth place alongside Darcey Harry from Wales. Harry had led the field by one shot after a third-round 68 but a closing 76 dropped her out of contention.
Austrian defending champion Isabella Hoplfer closed with a 1-under 71 to finish eighth at 289.